Question

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.


30 replies

Having the same problem..

I am forwarding a few messages from my gmail email account to my T-Mobile number so I can get text messages of those emails..

The last few days the T-Mobile service has been returning this error..

At first it was just having trouble and rejecting delivery.. Now its outright blocking the messages..

What is going on? I’m just a regular T-Mobile user with a personal phone number.. I don’t have a business account or anything.. I just want to forward some messages from my gmail to my phone as text messages.. What do I need to do to make that happen again?

It was working just fine last week, and for the last several months since I set it up.. But the past week its been failing, and now I’m getting this error.

Can someone help me with this please?

Thanks in advance!

Same issue here.. any status on resolution? 

I have critical home automation come through as text messages such as water leaks, fires, glass breaking etc. They are not coming through for about the past week. 

Please advise T-Mobile how to fix this?

 

 

Userlevel 7
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https://www.t-mobile.com/support/plans-features/consumer-versus-non-consumer-text-messaging

 

might be some needed info in here..

 

 

@srickar 

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Same here. I haven’t been getting my home automation notifications since Tuesday afternoon and all they do via support is give me the run around. I was supposed to get a tier 2 callback this morning at 9am, but they never called.

Maybe it’s time to switch to Verizon.. their offer for $30 a line for 4 lines for new users is tempting plus a credit to bringing your own phone. Hmmmm

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I’m seriously thinking about it. I’ve spent numerous hours with support on this. And even if they do fix the problem, I’ve noted that since sometime maybe around late March, my messages would be randomly delayed, sometimes over 24 hours.

It’s sad, because my first cell phone was with T-Mobile, and I remember back then the support was excellent - a gold standard by which I’ve judged subsequent support experiences… I ended up moving to Sprint a long time ago for their “Unlimited Everything” plan.  I’d noted that the support with Sprint wasn’t that great, but now that it’s back to T-Mobile, it’s *loads* worse.

Honestly, the path of least resistance is to switch my notifications to discord, but that just seems wrong. I *pay* for messaging and I’m supposed to get “support” if it’s not working, so I feel like changing providers simply out of disgust for what they’re putting me through. I get that the merging of networks is rough, so I’m trying to be tolerant, but if they’re not going to the effort to make the transition smooth for their customers, then it does not speak well for them.

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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...

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 🤷🏻

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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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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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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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.

I have been playing with the numbers and thought myself.  

 Still have a balance on 2 phones where the payout would be tough to swallow otherwise I would have gone already. 
 

 I’m paying for Matenta Max which should have priority data and it’s no better than when I was on my old plan.


Paying a premium and going backwards doesn’t bode well with me. Once I have a open I will strongly consider it. Service has not improved with Sprint that’s for sure. 

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

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.

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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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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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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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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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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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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https://www.markmonitor.com
 

they own Cloudfilter.net

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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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