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421 4.2.0 sender rejected AUP#SNDR


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I manage a few mail servers for my employer. We noticed that we are being blocked by T-Mobile (relay=tmo-east.mx.a.cloudfilter.net). We send a lot of messages to our customers' SMS gateway addresses daily.

As of today, all of our messages have started. On the servers we saw bouncing back with 421 sender rejected AUP#SNDR messages.

Is there any way you could whitelist our mail server IP addresses?  I know you are making some changes to fight spam, but it is hurting our clients who want to get notified on new property listings.

I can email the logs to you at an appropriate email address or complete a whitelist form if you would like, along with a list of our mail server IP addresses.

Please assist us with this issue.


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Thank you so much for this info.  It is extremely frustrating.  I completely agree with having a “spam” folder for the texts they are blocking.  We utilize a 3rd party app at work.  Which has 2 factor authentication set up.  This means the cell companies know the texts are coming from a legitimate site.   We would text are technicians info in the field directly from our software.  These guys are electricians who don’t have computers readily available when they are at a customers home.  Not having this feature is really causing issues.  What it comes down to is all the carriers want people to pay for sending texts like these.  It doesn’t matter that we as a company pay our cell phone bill and the recipient of these texts pay their own bill...they want to bill us on top of that.  Absolutely ridiculous.  Why when I am driving down the road and I pass a Kohls, I will receive a text about some coupon they are currently offering but if I sent a text from an authenticated app it doesn't go through????  

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I would love to see that apple script @hepcat72 . My Email to Text has been delayed/broken for weeks. Pretty much the exact issues described in this thread.

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For any others hampered by the random delays of home automation messages sent via your phonenumber@tmomail.net, I have written an AppleScript that can send either SMS (if your phone is on your WiFi) or iMessage (if you’re not on the same WiFi as the computer sending the text). The messages get through without the random delay caused by the spam filtering and I don’t *think* it’s subject to getting blocked.

The only problem is that it kind of defeats the purpose of wanting to send an SMS (if you don’t have a data signal), but I learned on Reddit that soon all calls and SMS messages will require a data connection anyway due to the decommissioning of the 2G network.

DM me if you’d like the script. I’ll probably blog it eventually.

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I learned via an SMS service called RingCentral that the spam filtering that was blocking my legitimate messages is due to new FCC rules about mobile carriers and spam filtering.

So I just submitted an FCC complaint at: https://consumercomplaints.fcc.gov/hc/en-us/requests/new?ticket_form_id=39744

that addresses what I believe to be an unintended side-effect: blocking of legitimate messages with little recourse for consumers. I suggest others facing these same issues should also submit their own complaints. Otherwise, we’re subject to arbitrary blocking of our own sent messages and messages we want to receive.

Here’s the content:

I have a series of home automations that use my mobile carrier's email-to-text feature to notify me when something notable happens in my home. These messages can include a security camera alert, motion alerts, moisture alarms, smoke detector alerts, etc., among other mundane messages. The average number of messages I receive per day using that feature is roughly 10 messages and I do not use it to send messages to anyone else. I set up an email account on gmail to be used exclusively for this purpose. I have used this method of messaging for years without issue until April/May of 2022.

On Tuesday July 19th, my home automation messages completely stopped. It took me many calls to tech support at both Sprint (my original carrier) and T-Mobile before the block on my email account was lifted. It took 2 weeks to resolve and they told me there are no guarantees it wouldn't get blocked again.

In talking with the last tech support guy who was able to identify and (temporarily) resolve the problem, I learned a few things:

1. T-Mobile contracts with a third party (a company called CloudMark) to perform spam filtering.
2. There is no way for a customer to directly request to CloudMark that a block on an email address to be lifted.
3. Tech support personnel are largely unaware of the spam filtering in use (which is why it took so many separate interactions and 2 weeks to resolve my issue).
4. Recipients have no way of knowing if a legitimate message sent to them has been spam filtered. (There's no way to for example, check a spam folder.)
5. The random message delivery delays (which can be in excess of 24 hours) are due to the spam filtering mechanism. This causes messages to arrive in a non-chronological order and can delay messages where timeliness is critical (e.g. my basement is flooding).

I have thoroughly researched this issue over the past 2 weeks and when considering whether or not to change carriers, I discovered that this is an issue with other carriers as well (e.g., Verizon) and is a fairly recent issue. I have interacted with a number of other people in forums who experienced the same problems as me.

I think users should have the right to whitelist messages sent to themselves or the senders as "not spam", because this spam filtering is blocking legitimate messages. Users should have the right to request compensation for failure to deliver messages. Users should also have the right to opt out of spam filtering for messages sent to them. There needs to be transparency all-around. Spam should be handled the same way as email providers do: create a spam box and give users controls to fine-tune their spam filtering.

At the very least, if the usage of email-to-text features are allowed to be limited by carriers or messages filtered without customers' knowledge or consent, users should be informed as to those limitations, such as number of recipients and/or messages allowed within a time window, the delays they can expect to experience in delivery, and what indicators are used to block either their own outgoing messages or messages sent to them. I tried to look up and requested those guidelines from T-Mobile and they had no information to offer that would enable me to avoid getting my email account blocked.

Furthermore, there should be honesty. The tech support person I spoke with claimed that Cloudmark said that other users identified my email account as a source of spam, despite the fact that I have NEVER sent a message from that account to anyone other than myself and there is zero evidence my account was hacked or that I have any other recipients in my sent mailbox other than myself.

 

And under the additional info, I entered:

This isn't about receiving an unwanted text - it's about not receiving a wanted text, but the categories provided don't account for this circumstance - please update your form to address mobile carriers blocking legitimate messages under the guise of spam filtering.

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Messages are again getting through.  It took a few hours after hanging up with Dan the other day for my messages to start coming though. Started getting messages that were sent within the past 2 days in random order.

Dan referred to the spam filtering company as “Cloudmark”. He said he has access to a ticket system to create tickets about issues like this. He said that regular users don’t have access to that ticketing system, but I did find this web form where you can submit a request to unblock an email address: https://www.cloudmark.com/en/contact.

Cloudmark responded to Dan’s ticket saying that “users” had reported messages coming from my email account as spam, which is obviously bullshit since I only EVER send messages to myself. They lifted the block on the email address, which is why messages started coming through.

The problem is that it could start happening again and there are no magic words I can say to a tech support person that will get me to someone who knows what to do.

I also brought up the issue of randomly delayed messages. Dan said he would create a ticket with cloudmark to address that.

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Finally talked to an engineer (Dan) that is familiar with the spam filtering they do. (I thought I commented this before here, but I don’t see it, so... I learned that the domain sending the “sender rejected” error [cloudfilter.net] is owned by markmonitor.com, which is the company that must have been contracted out by T-Mobile to do spam filtering.)

Dan said that he was already familiar with this issue because he is handling the same exact issue for another customer. And apparently he doesn’t have the capability of solving the issue directly. He created a ticket for the appropriate team to try and resolve the issue and said he would call me back.

I have 2 gmail accounts (one for my home automations that is blocked by markmonitor and one that I use as my primary email). I noted that if I send emails from my primary account, *sometimes* those messages get through and sometimes they’re blocked. The other account however hasn’t gotten a message through since 2 weeks ago and I checked that account for “sender rejected” error bouncebacks. I have 142 such bounceback errors. That’s about 10-12 messages per day on average over the past 13 days (though I don’t know if any of those bouncebacks are repeated - I don’t think so - each one is maybe the 3rd bounce-backs in a series of temporary delays that ends in the “sender rejected” error).

Dan said that it could take 24 hours for the spam team to address my issue. I guess we’ll find out...

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https://www.markmonitor.com
 

they own Cloudfilter.net

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And Cloudfilter runs via Amazon web services, which, if you sign up and read their stuff about email filtering, it has a mechanism for creating a “verified identity” for an email address. It's a long shot, but I started trying to do that, but it made me think that maybe if I send from my email that is on my sprint account… maybe it would magically work? I don't know. I'm grasping at straws.

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You know what? The hotspot data made me stop and think. If I'm going to pay more for less, I decided to search for people on Verizon that have the same problem that I'm trying to avoid… and I found them. There are users using phone@vtext.com (or whatever) to use email to text that are getting blocked but instead of cloudfilter.net, it's cloudmark.net (I think) that is bouncing back their emails. In fact I found a threads from consumers and business. The guy with the business said cloudmark has a form to submit to have his email domain whitelisted, but no one is responding to it. And he claimed there's no one at the cell carrier (Verizon) that even manages these things.

 

So it seems like there's no permanent way to avoid this issue… Really getting frustrated.

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I also learned that with my current Sprint plan, I have 60G mobile hotspot data. I also learned that our current taxes in NJ total $2.26. Assuming the taxes will be roughly equivalent, that puts the 5G Start Unlimited plan at $112.26/mo for 2 lines.

That’s roughly $4.26 more per month with 55G less hotspot data.

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So in preparation for making the switch to Verizon, I stopped by a T-Mobile store to drop off a Sprint Voice Pro device that they sent me awhile back to replace my Airave when my wife and I upgraded our phones (because they weren't compatible with the Airave anymore).

I brought up the issue of the email-to-text not working and the server bouncing back the emails with an error. The guy there confidently stated it was because of the Sprint network integration and said that migrating my account to T-Mobile would fix it. I couldn't remember at the time whether you ( @sdynak ) were already on TMo, but now I see you are when I review this thread.

So apparently the guy was bullshitting. Plus, they wouldn't take back the Voice Pro, but assured me that when I change providers, I'd be sent an RMA kit (though I'm really skeptical I won't get a whopper of a bill for it, given how discombobulated they all seem to be).

I did look at the magenta max plan though and it does appear to be cheaper than what I'm paying now. But if it won't solve this problem or the randomly slow texts or the choppy calls from inside our house even with WiFi calling enabled...


I am with T-Mobile and not from Sprint and on Magenta Max so it seems what he is telling you is BS. 
 

 And to add I have seen zero improvement since switching to Magenta Max. I was expecting priority service in crowded areas and nothing. I don’t have anything other than my own experience and no actual data or facts. Just had issues with data in every crowded situation since I switched. 

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So in preparation for making the switch to Verizon, I stopped by a T-Mobile store to drop off a Sprint Voice Pro device that they sent me awhile back to replace my Airave when my wife and I upgraded our phones (because they weren't compatible with the Airave anymore).

I brought up the issue of the email-to-text not working and the server bouncing back the emails with an error. The guy there confidently stated it was because of the Sprint network integration and said that migrating my account to T-Mobile would fix it. I couldn't remember at the time whether you ( @sdynak ) were already on TMo, but now I see you are when I review this thread.

So apparently the guy was bullshitting. Plus, they wouldn't take back the Voice Pro, but assured me that when I change providers, I'd be sent an RMA kit (though I'm really skeptical I won't get a whopper of a bill for it, given how discombobulated they all seem to be).

I did look at the magenta max plan though and it does appear to be cheaper than what I'm paying now. But if it won't solve this problem or the randomly slow texts or the choppy calls from inside our house even with WiFi calling enabled...

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not a whole lot to block your signal out on the water as long as the antenna is pointed your way and youre close enough lol.

 

homes/businesses the signal gets to fight against mother nature plus every wire/piece of metal in your home

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Hmmm… Yeah, the lack of a hotspot is somewhat of an issue. I rarely use it, but when I do, it’s usually really important.

 

 Exactly.. same here. How can I work from the boat without it 🤷🏻

does your phone have a signal when out on the boat?

 

 Yes, I just boat in the Barnegat Bay in NJ.. there is actually better service where I typically go vs. my home believe it or not LOL. 

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Hmmm… Yeah, the lack of a hotspot is somewhat of an issue. I rarely use it, but when I do, it’s usually really important.

 

 Exactly.. same here. How can I work from the boat without it 🤷🏻

does your phone have a signal when out on the boat?

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So I just chatted with a Verizon sales rep. Sounds like if you already have FIOS (which I do), you get $5/line/mo off from whichever plan you select. So if I went with the “Start” plan which includes 5 gigs of mobile hotspot, it would be $55/mo with autopay and paperless billing and FIOS discount. That’s the same as the welcome plan just with the hotspot added.  So $110/mo + taxes (compared to $108 with taxes/fees with Sprint/T-Mobile).  They said taxes depend on the state but they suggest expecting 10-15%. The upper end of that range would make my total (2-line) bill $126.50. It’s less hotspot data than I currently get, but I’m hoping the calls will be less choppy and that their email-to-text feature actually works - and would experience shorter latency than I was getting with T-Mobile compared to when it *was* working (which could have occasionally been in excess of 24h since this past April).

 

 Nice.. please, if you don’t mind let me/us know how the e-mail texting works out and overall if you are happy once you get a good test drive. I don’t have FIOS and it is not available to me. I can only get Verizon DSL which is a no go. I am stuck/cornered with Comcast/Xfinity. I understand they use Verizon so might be looking at that once the time comes. 

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So I just chatted with a Verizon sales rep. Sounds like if you already have FIOS (which I do), you get $5/line/mo off from whichever plan you select. So if I went with the “Start” plan which includes 5 gigs of mobile hotspot, it would be $55/mo with autopay and paperless billing and FIOS discount. That’s the same as the welcome plan just with the hotspot added.  So $110/mo + taxes (compared to $108 with taxes/fees with Sprint/T-Mobile).  They said taxes depend on the state but they suggest expecting 10-15%. The upper end of that range would make my total (2-line) bill $126.50. It’s less hotspot data than I currently get, but I’m hoping the calls will be less choppy and that their email-to-text feature actually works - and would experience shorter latency than I was getting with T-Mobile compared to when it *was* working (which could have occasionally been in excess of 24h since this past April).

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Hmmm… Yeah, the lack of a hotspot is somewhat of an issue. I rarely use it, but when I do, it’s usually really important.

 

 Exactly.. same here. How can I work from the boat without it 🤷🏻

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Hmmm… Yeah, the lack of a hotspot is somewhat of an issue. I rarely use it, but when I do, it’s usually really important.

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Actually, do you think that’s an introductory rate? I can’t tell. The name sounds like it’s introductory.

 

 I understood it as long as you stay on it that is what it is. I didn’t talk to anyone yet but I don’t think it’s introductory, but not for existing customers. 

Edit:

 Looking at some small print it does not include a hotspot which would be an issue for me. I don’t use it often but I do enough to require it. 

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I only have need for 2 lines. An equivalent plan is $70/mo/line plus taxes/fees, introductory rates aside. With taxes/fees, I currently pay $108/mo (both lines combined). Big difference.

  

 One bit of advice.. don’t get suckered into Magenta Max.. it’s no better then what you have today. trust me. I switched to it because the cost of the phones with the credits was a wash when I had 3 lines. Then my son dropped and the plan became a poor value for me and the wife only (2 lines also). If my work didn’t pay for ½ I would have switched already. I’m already paying it. 

My only concern was Verizon service and their fees. I have been down that road with them many years ago. 

 Good luck what you decide.

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Actually, do you think that’s an introductory rate? I can’t tell. The name sounds like it’s introductory.

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I only have need for 2 lines. An equivalent plan is $70/mo/line plus taxes/fees, introductory rates aside. With taxes/fees, I currently pay $108/mo (both lines combined). Big difference.

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I just checked out the Verizon plans. Much pricier than what I pay currently for whatever my plan is called now.  When I originally signed up, it was called “Unlimited Everything”. But… the verizon plan does come with Hulu and Disney+.  We were thinking about subscribing to Hulu anyway...

 

 Scroll down to the Welcome Unlimited plan.. $30 a month 4 lines. That’s pretty good!

 

 Plus $240 per line if you bring your own phone. 

 

 

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