Question

WIFI Calling Preferences Being Forced to Cellular Preferred

  • 10 October 2020
  • 62 replies
  • 12129 views

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I am experiencing my WIFI Calling Preferences always being forced to “cellular preferred”, as are others.   I live in an area with poor T-mobile mobile data signal and this recent behavior makes my phone unable to make and receive calls and text messages.   I believe the problem only started happening after the next to last T-Mobile software update.  Everything was fine for my first 5 months of ownership.  A Google search shows posts of other users experiencing the same issue, but no options other than a tedious workaround of manually switching the phone to Airplane mode and changing the WIFI calling preferences back to “WIFI preferred”.  I have to do this kind of process each time I enter and leave my home, and sometimes have to reboot my phone as well.   The times I’ve forgotten, I’ve missed package deliveries and went to a doctor appointment when the doctor had left a message that he was out sick.  This appears to be a carrier specific issue as far as I can see.   I even tried replacing my rock solid Netgear R6400 router with an ASUS AX3000 router with no resulting changes.   I’m in a small apartment only 10 feet from the router, with a very strong WIFI signal.  I have two Samsung Galaxy S20 phones (March 2020) which both exhibit the exact same behavior.   I spoke with T-Mobile Tech support which appeared to be clueless about this issue other than to send me two new S20 phones under warranty to my T-Mobile store.   I do not have high confidence in this approach but will try the new phones and report back. 

Does anyone know anything more?   I am not aware of T-Mobile publicly acknowledging this issue.


62 replies

This will be my last post on the Wi-Fi preferences changed issue. Once I switch carriers, I will have no reason to say anything else.

I have three issues

  1. My Calling preference for Wi-Fi calling being changed to Cellular against my wishes. No, my preference didn't change, it was changed without my permission.
  2. While using Wi-Fi calling, some incoming calls are missed. This has no relation to #1, since it happens when I am in Airplane mode with Wi-Fi and Wi-Fi calling turned on. My preference for Wi-Fi calling isn't changed.
  3. T-Mobile customer support does not have the practices and procedures to support their customers with this issue. T-Mobile and Samsung seem to not have the competence or desire to fix this issue.

I switched to T-Mobile specifically to get Wi-Fi calling. We traveled to Sedona on vacation and stayed in a resort in the Oak Creek Canyon wilderness area. The resort offered Wi-Fi, but there is no cellular service in this area. To use my cell phone, I would need Wi-Fi calling. My T-Mobile phone worked without problems on this trip. In future trips we have stayed in remote accommodations not offing cellular service but with Wi-Fi. My Wi-Fi calling has worked flawlessly.

But with what I have heard called as the Pie update, Wi-Fi calling has been an issue. For a couple of years T-Mobile customers needing Wi-Fi calling due to no or inconsistent cellular service, Wi-Fi calling has been unreliable. No suggested settings, no workarounds, no updates fix or mitigate the problem.

More disappointing is the incompetence I have seen in customer support. T-Mobile practices and procedures, as well as the technology used to support contacting the customer have exacerbated the issue. Customer support does not get back to the customer when a response is promised. Customer support seems to not understand the serious of the issue to the customer.

I have used and worked in IBM customer support. Their system is oriented in getting solutions and keeping the customer informed of the progress of the solution. The support system keeps a knowledge base of known problems and solutions, and reminds customer support when a response is due to the customer. The T-Mobile system seems to offer none of these important features.

I was employed at IBM when Lou Gertsner was hired to do its turn-around. He told us anyone dealing directly with a customer was in sales. I was skeptical, but came to understand what he was saying. It is especially true today when most of our interaction with companies is through the internet. Unless we visit a T-Mobile store, our dealings are with customer support. They don't sell us things, but they can definitely make us ex-customers. Poor customer support and inability to fix or understand the customer's problem makes the customer to look for solutions elsewhere.

I was at such frustration with phone customer support I wrote a letter to corporate customer support and heard back from a corporate rep. I was in negotiations for a solution when the rep seems to have disappeared. No rep, no solution. Only silence.

Although my cellular service is still weak, and very weak or nonexistent in parts of my house, I have turned off Wi-Fi calling for now. I spend most of my time at home in my man cave, and the T-Mobile signal is strongest (usually 1-2 bars) in this room. I leave Wi-Fi on for other functions to work in weak signal areas. This works at home, but I will need reliable Wi-Fi calling on vacations, so I need to find a cellular service that supports reliable Wi-Fi calling.

I don't use 5G now, and probably won't need it for a while. I don't game or stream. But since it is available, I will get a 5G capable phone when I switch. What makes this decision sad is T-Mobile is poised to offer the best 5G C-Band service, as Sprint owned a good number of the C-Band frequencies.

I am looking at 3 Verizon network options

  • CREDO - good but not lowest price for my usage, but among the best customer support. Online only.
  • Spectrum Mobile - best pricing, but very new at the customer support business for cellular service. Does have a local office.
  • Verizon - Owns and controls the network. Not best pricing. As a previous customer, the support was good.

I set my Galaxy S9 to airplane mode, then turned on Wi-Fi and Wi-Fi calling last night. It should never switch to cellular and always be active on the internet. This afternoon, I called my cell from my home phone and got the message ‘This phone is not accepting calls, try again later’. Five minutes later I tried again and my phone rang almost immediately. Five minutes later I tried again and after about 30 seconds I was sent to my voicemail. This has to be a phone and T-Mobile Wi-Fi calling network issue.

There is no workaround for this problem, and T-Mobile and Samsung seem unable to fix it. If you need to use Wi-Fi calling when you have poor cellular service, expect to miss a lot of calls.

The only fix on T-Mobile is to switch from a Samsung phone to another cellular phone company product. This probably means a phone upgrade at regular price to fix a problem caused by T-Mobile and Samsung. 

If you like Samsung phones, like I do, the solution is to switch to another cellular provider. I have Spectrum Mobile in my area and their price for a senior citizen not using much high speed data is much cheaper than my T-Mobile plan. The problem is it uses the Verizon network and my S9 is not supported. I will have to get a new phone, but even then if I use less than 1 Gig per month the Spectrum plan cost will still be less than my current T-Mobile plan, even paying for a new phone.

The secondary issue I have is with customer support. My problem was forwarded to Technical Support and I was told to expect a callback. A week later, after no callback, I called in again and eventually was connected to Technical Support. They had me try a few things, but nothing corrected the problem.

I am in contact (I thought) with corporate customer support, but after first contact they seem to be ignoring me as well.

I get the feeling they want customers with problems they can’t fix to go away.

They will soon get their wish.

I am working with T-Mobile corporate to try to resolve/mitigate my issues. Like most here, I have the Wi-Fi optimization issue, switching from Wi-Fi to cellular, even though I am just feet away from a very good ASUS router. My cellular signal strength varies from 2-3 in the best location to 1 or none in other areas. I want to be able to take my phone anywhere in my house and not lose a call. This originally worked great with Ethernet connected CellSpot routers, but died after a software update. Many updates later and still doesn’t work reliably. I since upgraded to ASUS RT-AC86U routers, hoping to have better connectivity and reducing the impact of leaving T-Mobile. Didn’t help my Wi-Fi optimization problem, but my kids notice the faster speed when they visit.

Call support was no help. Every suggestion failed.

I have an additional issue that I haven’t seen explicitly addressed. I frequently have incoming calls routed directly to voicemail after what seems to be a futile attempt by the T-Mobile network to locate my phone. It takes about 30 seconds for this to happen. The voicemail notification may be quick, or it may take a while to appear. This can happen when in cellular or Wi-Fi mode. It might be after a phone directed optimization takes place, but no way to know for certain.

Being old, I don’t game or watch videos (other than news or weather), so my phone is primarily for communication. Since it often fails to communicate, I consider it defective and subject to replacement under my T-Mobile warranty. The problem is getting a replacement phone that doesn’t have the problem.

To be certain to remedy this issue on T-Mobile, that means an iPhone.

Since this problem seems to be exclusive to T-Mobile, it is actually cheaper for me to switch to Spectrum Mobile using the $14 per Gig plan. 

If T-Mobile doesn’t have a solution soon, I may have to switch.  

I have Note 10, Note 10+ and Note 20 Ultra5G. They all have this issue. I updated the phones and did factory reset also but I still have this issue.

I rely on Wifi calling at home and with this feature gone the phones are useless.

When will this be resolved or else it might be time to such back to iOS.

I am experiencing my WIFI Calling Preferences always being forced to “cellular preferred”, as are others.   I live in an area with poor T-mobile mobile data signal and this recent behavior makes my phone unable to make and receive calls and text messages.   I believe the problem only started happening after the next to last T-Mobile software update.  Everything was fine for my first 5 months of ownership.  A Google search shows posts of other users experiencing the same issue, but no options other than a tedious workaround of manually switching the phone to Airplane mode and changing the WIFI calling preferences back to “WIFI preferred”.  I have to do this kind of process each time I enter and leave my home, and sometimes have to reboot my phone as well.   The times I’ve forgotten, I’ve missed package deliveries and went to a doctor appointment when the doctor had left a message that he was out sick.  This appears to be a carrier specific issue as far as I can see.   I even tried replacing my rock solid Netgear R6400 router with an ASUS AX3000 router with no resulting changes.   I’m in a small apartment only 10 feet from the router, with a very strong WIFI signal.  I have two Samsung Galaxy S20 phones (March 2020) which both exhibit the exact same behavior.   I spoke with T-Mobile Tech support which appeared to be clueless about this issue other than to send me two new S20 phones under warranty to my T-Mobile store.   I do not have high confidence in this approach but will try the new phones and report back. 

Does anyone know anything more?   I am not aware of T-Mobile publicly acknowledging this issue.

AGREED!!! Not Tmobiles business weather we have that setting on or off. Why have the setting if we can't use it. Might as well be grayed out in the menu.

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The issue appears to be: how can you advertise a feature that clearly does not work? The old “truth in advertising” problem. I think that correcting this issue should be a technical priority for T-Mobile.

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It seems to me that many are having this identical problem… those of us who depend on wi-fi connectivity because we live in a hi-rise building or in an area with poor cell coverage. These wi-fi connectivity issues began with a system update in mid-2020. If you select “wi-fi preferred” within a short period of time your phone will revert to “cellular preferred”. T-mobile has given me different phones and the same thing happens on all of them.  Worse yet, I have had multiple instances of an incoming call -- when on a wi-fi system -- going directly to voice mail and my cell phone never rings. I have observed this issue myself by calling my cell phone from a landline phone. I have tried temporarily deleting various apps from my phone -- but the same issue persists. This is not, I think, from my phone, my apps, or the wi-fi network I am on. It seems to be a software issue. Complaints are coming from Android and Apple users which are similar. Should not T-Mobile get this technically resolved? And would it not be honest to send out a blanket announcement to T-Mobile customers that “wi-fi is not working properly and we are working on it” or something like that? It seems to me that it is not fair or honest to advertise a service which is not properly working. Or openly solicit any problems we are having with T-Mobile wi-fi connectivity. I really love T-Mobile availability most places in the world -- buy the wi-fi connectivity is a big issue for me.

It is disturbing that nothing is being done to remedy this problem….and that T-Mobile will not even acknowledge it. There is an obvious issue here that needs immediate resolution. Perhaps public awareness is low because it mainly affects folks who don’t have the best cellular connection and even then, most folks would likely be unaware of why the were missing texts and calls. It really does seem to be from our phones spontaneously switching to “Cellular Preferred”. Wait, whose preference is that? Mine?….or the phone’s? Can’t I lock in MY preferences? What’s that setting for? Who’s it for? If it’s on “Cellular Preferred” and there is poor cellular service at that location (although there may be good wifi) you will miss calls and texts. Such has been my situation for the last 6 months or so. 

As much as I’ve loved T-Mobile for the last 8 years, they seem to have gone downhill. This is truly unacceptable and I am ready to change carriers. If I see no real changes, or at least an explanation and attempt to fix this, I will make it my mission to make this issue, and their lack of response, as public as possible and get the word out nationwide…..there’s a big problem and T-Mobile refuses to not only fix it, but to even acknowledge it!

I have the same issue as reported by many other users: on Samsung A32 5G (SM-A326U) the WiFi calling preference is constantly being reset from WiFi-preferred to cellular preferred.

T-MOBILE needs to work with Samsung to address the issue!

I continue to have the “Wi F calling preferences updated to optimize network experience” message appear on my Galaxy S9 constantly. It is changed from Wi-Fi to cellular, even though I have only one bar on cellular service and am 5 feet away from my ASUS RT-AC86U router. It seems like I miss calls when it is reset to cellular preferred.

I have many issues with this unwanted “service”. If I set a preference, it is what I want and I expect my preference to be honored. Is this reset only on my phone, or is it also recognized by T-Mobile so if I get a call T-Mobile will only use cellular and not work if I don’t have sufficient coverage?

T-Mobile has replaced my SIM card, but that didn;t help. There was a suggestion to clear the cache partition and reset network connection. I have done this repeatedly and it doesn’t work.

It looks like I have three solutions: Take my Galaxy S9 to AT&T, stay with T-Mobile and replace my Samsung with a different manufacturer’s cell phone, or go to Spectrum/Verizon and get a new phone.

Note to T-Mobile: If you are monitoring this issue, please respond.

Thanks for the update emergency dentist

IT looks like this has been fixed.  The latest update for My S21 leaves WiFi preferred, locked in. 

Can't believe I have to switch to verizon because of this

Bottom line primary trigger causing “Cellular Preferred” changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.  

bottom line primary trigger causing “Cellular Preferred” changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.  Wifi scanning basically momentarily pauses or severely limits your current wifi connection while the radio adjusts between wifi channels trying to locate other networks to meter yours against, causing the wifi calling app to disconnect unexpectedly and flip to cellular

Bottom line primary trigger causing “Cellular Preferred” changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.  Wifi scanning basically momentarily pauses or severely limits your current wifi connection while the radio adjusts between wifi channels trying to locate other networks to meter yours against, causing the wifi calling app to disconnect unexpectedly and flip to cellular. 

Bottom line primary trigger causing “Cellular Preferred” changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.  Wifi scanning basically momentarily pauses or severely limits your current wifi connection while the radio adjusts between wifi channels trying to locate other networks to meter yours against, causing the wifi calling app to disconnect unexpectedly and flip to cellular. This in turn blows for us all because it is implemented into almost all newly developed/updated apps to be allowed in the Google Play Store, even the built in Android app that senses input from a simple touch of your touch screen and keyboard apps cause wifi scanning to momentarily take place, had mine changing it seemed 50% of the time swiping my screen to unlock. The standard Android settings menu allows you turn off wifi scanning so they make it seem but this toggle only disables wifi scanning features at user level installed apps, not wifi and GPS scanning for system based ones provided by Android/vendor/Google.

Having an E911 address set in the first place is the first essential part for Voice over LTE, video calling, and WiFi calling features to become active and usable at all in the first place, otherwise yours was functionally disabled without it, even though the toggle is there, with no E911 it causes IMS registration to fail, dis-allowing these functions entirely from the cell tower on device bootup. Testing with Airplane mode on then wifi, calls will drop regardless if E911 address is not in place, IMS Registration status is verified in SIM card status will tell you if Voice over LTE, video calling, and WiFi calling features are active and functioning Now that you have it, it WILL be a matter of time until you find this setting changing to cellular preferred constantly occurring throughout use as most ALL other carriers included Android 9+ Google software bundled phones go. Tracing through logs in App Ops I have identified this change over issue down to a combination of all softwares, implemented first by Google through most any Play Store apps eventually brought into standard Android OS development and also infused into vendor/carrier installed apps just the same is the ongoingly largest battery draining issue - randomly occurring wifi scanning also mixed in with Geo Location/NFC triggers which are all binded directly with GPS Location Services function. 

Getting an E911 address set in the first place is the first essential part for Voice over LTE, video calling, and WiFi calling features to become active and usable at all in the first place, otherwise yours was functionally disabled without it, even though the toggle is there, with no E911 it causes IMS registration to fail, dis-allowing these functions entirely from the cell tower on device bootup. Testing with Airplane mode on then wifi, calls will drop regardless if E911 address is not in place, IMS Registration status is verified in SIM card status will tell you if Voice over LTE, video calling, and WiFi calling features are active and functioning Now that you have it, it WILL be a matter of time until you find this setting changing to cellular preferred constantly occurring throughout use as most ALL other carriers included Android 9+ Google software bundled phones go. Tracing through logs in App Ops I have identified this change over issue down to a combination of all softwares, implemented first by Google through most any Play Store apps eventually brought into standard Android OS development and also infused into vendor/carrier installed apps just the same is the ongoingly largest battery draining issue - randomly occurring wifi scanning also mixed in with Geo Location/NFC triggers which are all binded directly with GPS Location Services function. Bottom line primary trigger causing “Cellular Preferred” changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything. 

The only select few apps I set to allow location access to is Google Maps cloned along with google play services, isolated in my cloned Island work profile for when needed , then two I set to “allow only while using the app which are both needed for IMS registration to successfully complete at boot: DiagMonAgent and IMS Service. Since IMS registration takes place only once on devices at bootup, if I have wifi left on before rebooting it may trip to Cellular Preferred only once just at this moment depending how fast wifi connects vs completion of IMS registation. So as long as I don’t restart with wifi on my issue is now 100% resolved and now completely entirely non-existent, “WiFi Preferred” calling mode is now holding persistently, only now accurately displaying unavailable currently when wifi diminishes before dropping or as changing WiFi to another connection, IMS re-establishes and maintains “WiFi Preferred” option through every transition. The other guy can above can run back to Verizon if so he chooses but either way we ALL live in this Google/Microsoft driven world whom both want to know every last detail of none other than you, good luck getting them to change their ways or to get your new carrier to sell you a device that has neither but works on their network, otherwise mod your own device you personally own how you like the way, we in the free/open-source Linux community, always have. Windows 95 does still function also if you so choose to use it for something or like demonstrating how things USED to work in days of ol, but if you want to use it with today’s world of software and hardware both, you won’t have much luck.  If you merely buy a device from any standard Cell Phone Carrier you are in fact buying into their whole entire knowledgeably ignorant scheme to hand them hundreds of dollars only because their service is somehow unexplainably “better” than their identical competition with identical devices and consolidated shared Cell towers, sales are not developers are not technicians, continue the endless loop. Open source already fixed the problem, Google and Microsoft never will because it is 100% strictly marketing based and profiting them, if a product doesn’t work well or no longer does after being updated to “latest improved software” you’ll come shovel out hundreds for another new one to replace a 6 month old new one….right??? There are other forums for those carriers too once you find yourself in the exact same current situation once your new device updates itself. Also good preventative to avoid vendor forced OS updates that some have found their devices booting up to regardless of disabling automatic system updates (vendor/carriers do have the ability to and do force system updates occasionally in waves to all devices reporting not being updated after a set time duration expires pushed through SMS/GMS code in the System Update app) if using Island then freeze (disabled until YOU open it)the update app and only update once you know updates are stable, most vendors wait months after security updates are released before they push them to available for your device to see in the first place so a little extra time on your end to actually verify stability between other actual users will keep this and any other unexpected downgraded updates from disrupting life

Having an E911 address set in the first place is the first essential part for Voice over LTE, video calling, and WiFi calling features to become active and usable at all in the first place, otherwise yours was functionally disabled without it, even though the toggle is there, with no E911 it causes IMS registration to fail, dis-allowing these functions entirely from the cell tower on device bootup. Testing with Airplane mode on then wifi, calls will drop regardless if E911 address is not in place, IMS Registration status is verified in SIM card status will tell you if Voice over LTE, video calling, and WiFi calling features are active and functioning Now that you have it, it WILL be a matter of time until you find this setting changing to cellular preferred constantly occurring throughout use as most ALL other carriers included Android 9+ Google software bundled phones go. Tracing through logs in App Ops I have identified this change over issue down to a combination of all softwares, implemented first by Google through most any Play Store apps eventually brought into standard Android OS development and also infused into vendor/carrier installed apps just the same is the ongoingly largest battery draining issue - randomly occurring wifi scanning also mixed in with Geo Location/NFC triggers which are all binded directly with GPS Location Services function. Bottom line primary trigger causing “Cellular Preferred” changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.  Wifi scanning basically momentarily pauses or severely limits your current wifi connection while the radio adjusts between wifi channels trying to locate other networks to meter yours against, causing the wifi calling app to disconnect unexpectedly and flip to cellular. This in turn blows for us all because it is implemented into almost all newly developed/updated apps to be allowed in the Google Play Store, even the built in Android app that senses input from a simple touch of your touch screen and keyboard apps cause wifi scanning to momentarily take place, had mine changing it seemed 50% of the time swiping my screen to unlock. The standard Android settings menu allows you turn off wifi scanning so they make it seem but this toggle only disables wifi scanning features at user level installed apps, not wifi and GPS scanning for system based ones provided by Android/vendor/Google. Only time when wifi scanning ideally should be occuring is when you are in your list of connections making a choice to connect to. Appops is implemented into all versions of Android already at the command line level as DOS is to windows so it works as a one-time direct command adjusting permissions/settings directly and instantly, not like other apps which run receivers to trigger scripts continually draining battery/hindering function. Play Store App Ops gives you the graphical interface to utilize it easily(internally utilizing ADB at boot sequence to apply changes all at once or all can be disabled just the same if issue were to arise tweaking without research), allowing you to directly set system app and user app permissions to ignore these requests with blank data(rather than blocking and crashing app). 

Having an E911 address set in the first place is the first essential part for Voice over LTE, video calling, and WiFi calling features to become active and usable at all in the first place, otherwise yours was functionally disabled without it, even though the toggle is there, with no E911 it causes IMS registration to fail, dis-allowing these functions entirely from the cell tower on device bootup. Testing with Airplane mode on then wifi, calls will drop regardless if E911 address is not in place, IMS Registration status is verified in SIM card status will tell you if Voice over LTE, video calling, and WiFi calling features are active and functioning Now that you have it, it WILL be a matter of time until you find this setting changing to cellular preferred constantly occurring throughout use as most ALL other carriers included Android 9+ Google software bundled phones go. Tracing through logs in App Ops I have identified this change over issue down to a combination of all softwares, implemented first by Google through most any Play Store apps eventually brought into standard Android OS development and also infused into vendor/carrier installed apps just the same is the ongoingly largest battery draining issue - randomly occurring wifi scanning also mixed in with Geo Location/NFC triggers which are all binded directly with GPS Location Services function. Bottom line primary trigger causing “Cellular Preferred” changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.  Wifi scanning basically momentarily pauses or severely limits your current wifi connection while the radio adjusts between wifi channels trying to locate other networks to meter yours against, causing the wifi calling app to disconnect unexpectedly and flip to cellular. This in turn blows for us all because it is implemented into almost all newly developed/updated apps to be allowed in the Google Play Store, even the built in Android app that senses input from a simple touch of your touch screen and keyboard apps cause wifi scanning to momentarily take place, had mine changing it seemed 50% of the time swiping my screen to unlock. The standard Android settings menu allows you turn off wifi scanning so they make it seem but this toggle only disables wifi scanning features at user level installed apps, not wifi and GPS scanning for system based ones provided by Android/vendor/Google. Only time when wifi scanning ideally should be occuring is when you are in your list of connections making a choice to connect to. Appops is implemented into all versions of Android already at the command line level as DOS is to windows so it works as a one-time direct command adjusting permissions/settings directly and instantly, not like other apps which run receivers to trigger scripts continually draining battery/hindering function. Play Store App Ops gives you the graphical interface to utilize it easily(internally utilizing ADB at boot sequence to apply changes all at once or all can be disabled just the same if issue were to arise tweaking without research), allowing you to directly set system app and user app permissions to ignore these requests with blank data(rather than blocking and crashing app). The only select few apps I set to allow location access to is Google Maps cloned along with google play services, isolated in my cloned Island work profile for when needed , then two I set to “allow only while using the app which are both needed for IMS registration to successfully complete at boot: DiagMonAgent and IMS Service. Since IMS registration takes place only once on devices at bootup, if I have wifi left on before rebooting it may trip to Cellular Preferred only once just at this moment depending how fast wifi connects vs completion of IMS registation. So as long as I don’t restart with wifi on my issue is now 100% resolved and now completely entirely non-existent, “WiFi Preferred” calling mode is now holding persistently, only now accurately displaying unavailable currently when wifi diminishes before dropping or as changing WiFi to another connection, IMS re-establishes and maintains “WiFi Preferred” option through every transition. The other guy can above can run back to Verizon if so he chooses but either way we ALL live in this Google/Microsoft driven world whom both want to know every last detail of none other than you, good luck getting them to change their ways or to get your new carrier to sell you a device that has neither but works on their network, otherwise mod your own device you personally own how you like the way, we in the free/open-source Linux community, always have. Windows 95 does still function also if you so choose to use it for something or like demonstrating how things USED to work in days of ol, but if you want to use it with today’s world of software and hardware both, you won’t have much luck.  If you merely buy a device from any standard Cell Phone Carrier you are in fact buying into their whole entire knowledgeably ignorant scheme to hand them hundreds of dollars only because their service is somehow unexplainably “better” than their identical competition with identical devices and consolidated shared Cell towers, sales are not developers are not technicians, continue the endless loop. Open source already fixed the problem, Google and Microsoft never will because it is 100% strictly marketing based and profiting them, if a product doesn’t work well or no longer does after being updated to “latest improved software” you’ll come shovel out hundreds for another new one to replace a 6 month old new one….right??? There are other forums for those carriers too once you find yourself in the exact same current situation once your new device updates itself. Also good preventative to avoid vendor forced OS updates that some have found their devices booting up to regardless of disabling automatic system updates (vendor/carriers do have the ability to and do force system updates occasionally in waves to all devices reporting not being updated after a set time duration expires pushed through SMS/GMS code in the System Update app) if using Island then freeze (disabled until YOU open it)the update app and only update once you know updates are stable, most vendors wait months after security updates are released before they push them to available for your device to see in the first place so a little extra time on your end to actually verify stability between other actual users will keep this and any other unexpected downgraded updates from disrupting life.

Welcome to customer support and sales experience. Thats precisely why I am a technician now, I see no point in ignorantly lying aimlessly to people just to make more sales. Pretty disgracing of a customer service team though altogether, never in my life, let alone on multiple recent hour plus long calls to these “let play stupid and clueless” antic assholes, if you have noise cancellation off on your sound you can here the agent and the group of thieves surrounding them in a hopeless lonely cubicle literally laughing along while saying they have never heard of this in all their years in prepaid/postpaid support, it has to be your phone, come into our store and we’ll explain it all for you with a new $1800, all glass cased device with new 5G technology which is slower and less storage capacity than your outdated IP68 military grade rating that runs smoother and faster than new, only functioning thing accounting for this $1400 price difference is an updated over-rated high mega-pixel camera that actually takes the same 1080p picture edited with software rendering, also of which comes standard on $100 price range models today

Thanks for jumping in with this….but, unfortunately this doesn’t solve the problem. I’ve had all my phones properly set up with e911 and still have the same problem. I certainly wish it was that simple!

Today I was on the phone with tech support for over two hours. I was not impressed with their level of knowledge (on anything!). Surprisingly (or maybe not) the first level support person I spoke with had never heard of this problem (it didn’t help that she was so heavily accented I couldn’t understand her half the time …..why do they use those folks for tech support???). I assured her that it was all over the internet. Ultimately I explained in detail the situation and she consulted other support folks and came up with a workaround. Not a great one certainly, but something that should help….at least at my house. The workaround? A cell phone signal booster. They’ve agreed to send me one (a loaner w’ a $25 deposit). In theory, this will amplify the 4G LTE signal enough that, if, by chance, my phone randomly switches from WiFi preferred to Cellular preferred at least the cellular signal will be strong enough that I can still send and receive calls/texts. This does not change the annoying fact that the phone won’t stay on WiFi preferred. Annoying also because, not only am I unable to get texts or make calls when it swaps, but if it does swap to cellular and still works, I unknowingly use cellular data rather than Wifi data so it can end up costing more. And I will still have the issue at my vacation home where the problem is far worse (they’ll only give me one of these boosters!). At this date there is no proposed fix for the random swapping to cellular preferred….unless you use “DazedandConfused” method which I’m not quite up to tackling at this point (his method would likely leave me dazed and confused!). They did suggest to turn on airplane mode and then turn WiFi on…..this would keep it from going to cellular….but, as I pointed out to them, then if you wonder away from your wifi (you might forget) you get absolutely nothing. That’s even worse! Apparently all android phones...especially Samsung ...have been plagued by this after an update about 6 months ago. In hindsight, this would have been the time to swap to an iPhone. Certainly the android folks will come up with a real fix….right???   Although I guess I can’t really blame T-Mobile for all of this, I’m still very disappointed in their tech support…..they should have had this all figured out with all possible workarounds….it shouldn’t take two hours! 

Having an E911 address set in the first place is the first essential part for Voice over LTE, video calling, and WiFi calling features to become active and usable at all in the first place, otherwise yours was functionally disabled without it, even though the toggle is there, with no E911 it causes IMS registration to fail, dis-allowing these functions entirely from the cell tower on device bootup. Testing with Airplane mode on then wifi, calls will drop regardless if E911 address is not in place, IMS Registration status is verified in SIM card status will tell you if Voice over LTE, video calling, and WiFi calling features are active and functioning Now that you have it, it WILL be a matter of time until you find this setting changing to cellular preferred constantly occurring throughout use as most ALL other carriers included Android 9+ Google software bundled phones go. Tracing through logs in App Ops I have identified this change over issue down to a combination of all softwares, implemented first by Google through most any Play Store apps eventually brought into standard Android OS development and also infused into vendor/carrier installed apps just the same is the ongoingly largest battery draining issue - randomly occurring wifi scanning also mixed in with Geo Location/NFC triggers which are all binded directly with GPS Location Services function. Bottom line primary trigger causing “Cellular Preferred” changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.  Wifi scanning basically momentarily pauses or severely limits your current wifi connection while the radio adjusts between wifi channels trying to locate other networks to meter yours against, causing the wifi calling app to disconnect unexpectedly and flip to cellular. This in turn blows for us all because it is implemented into almost all newly developed/updated apps to be allowed in the Google Play Store, even the built in Android app that senses input from a simple touch of your touch screen and keyboard apps cause wifi scanning to momentarily take place, had mine changing it seemed 50% of the time swiping my screen to unlock. The standard Android settings menu allows you turn off wifi scanning so they make it seem but this toggle only disables wifi scanning features at user level installed apps, not wifi and GPS scanning for system based ones provided by Android/vendor/Google. Only time when wifi scanning ideally should be occuring is when you are in your list of connections making a choice to connect to. Appops is implemented into all versions of Android already at the command line level as DOS is to windows so it works as a one-time direct command adjusting permissions/settings directly and instantly, not like other apps which run receivers to trigger scripts continually draining battery/hindering function. Play Store App Ops gives you the graphical interface to utilize it easily(internally utilizing ADB at boot sequence to apply changes all at once or all can be disabled just the same if issue were to arise tweaking without research), allowing you to directly set system app and user app permissions to ignore these requests with blank data(rather than blocking and crashing app). The only select few apps I set to allow location access to is Google Maps cloned along with google play services, isolated in my cloned Island work profile for when needed , then two I set to “allow only while using the app which are both needed for IMS registration to successfully complete at boot: DiagMonAgent and IMS Service. Since IMS registration takes place only once on devices at bootup, if I have wifi left on before rebooting it may trip to Cellular Preferred only once just at this moment depending how fast wifi connects vs completion of IMS registation. So as long as I don’t restart with wifi on my issue is now 100% resolved and now completely entirely non-existent, “WiFi Preferred” calling mode is now holding persistently, only now accurately displaying unavailable currently when wifi diminishes before dropping or as changing WiFi to another connection, IMS re-establishes and maintains “WiFi Preferred” option through every transition. The other guy can above can run back to Verizon if so he chooses but either way we ALL live in this Google/Microsoft driven world whom both want to know every last detail of none other than you, good luck getting them to change their ways or to get your new carrier to sell you a device that has neither but works on their network, otherwise mod your own device you personally own how you like the way, we in the free/open-source Linux community, always have. Windows 95 does still function also if you so choose to use it for something or like demonstrating how things USED to work in days of ol, but if you want to use it with today’s world of software and hardware both, you won’t have much luck.  If you merely buy a device from any standard Cell Phone Carrier you are in fact buying into their whole entire knowledgeably ignorant scheme to hand them hundreds of dollars only because their service is somehow unexplainably “better” than their identical competition with identical devices and consolidated shared Cell towers, sales are not developers are not technicians, continue the endless loop. Open source already fixed the problem, Google and Microsoft never will because it is 100% strictly marketing based and profiting them, if a product doesn’t work well or no longer does after being updated to “latest improved software” you’ll come shovel out hundreds for another new one to replace a 6 month old new one….right??? There are other forums for those carriers too once you find yourself in the exact same current situation once your new device updates itself. Also good preventative to avoid vendor forced OS updates that some have found their devices booting up to regardless of disabling automatic system updates (vendor/carriers do have the ability to and do force system updates occasionally in waves to all devices reporting not being updated after a set time duration expires pushed through SMS/GMS code in the System Update app) if using Island then freeze (disabled until YOU open it)the update app and only update once you know updates are stable, most vendors wait months after security updates are released before they push them to available for your device to see in the first place so a little extra time on your end to actually verify stability between other actual users will keep this and any other unexpected downgraded updates from disrupting life

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