Email to SMS via Not Working

  • 14 September 2023
  • 14 replies


As of Sept 11 my alarm systems stopped sending me notifications via email to sms utilizing After some troubleshooting we have concluded that the email system is failing:


Could not deliver message to the following recipient(s):

Failed Recipient:

Reason: Remote host said: 452 4.1.0 server temporarily unavailable AUP#MXRT

Is anyone else experiencing this issue? Any idea how to fix it? How to escalate it? We will be missing security/fire/medical alerts!


Best answer by lfolks 31 October 2023, 21:46

View original

14 replies

I have also noticed that messages inbound to my t-mobile e-mail address do not arrive as SMS messages as of the last week or so. There was a moment where it worked for a few hours 3ish days ago, but it again doesn’t work.

Userlevel 7
Badge +11

As usual, it works for me. Almost instantaneous.

Not working this morning

server temporarily unavailable AUP#MXRT


Userlevel 1

Same here.. any luck anyone? 

Same thing here when trying to send email messages to my phone number via Home Assistant and for around the same amount of time too.  I’d been thinking it was a Gmail issue all this time as I keep getting delayed/failure notifications from Gmail including this line at the bottom.  

 The response from the remote server was:

452 4.1.0 <> server temporarily unavailable AUP#MXRT

Userlevel 1

Yup.. I’m using Universal Devices.. I have been giving it time thinking it would have been resolved by now but doesn’t seem promising. 

 Might be time to go with Xfinity and get the discounts. T-Mobile don’t seem to give a  on this issue. 


Same thing started happening to me a few days ago.

I’m in the Nashville area if that means anything.

My cable is AT&T and they are always offering me “plans” if I add cellphone.

But I hate AT&T more then I hate T-M


It was working for a while now it isn’t.  I get what is shown below.

Maybe it is time to create a database where users can add a line every time a message doesn’t get through.

Anybody have an idea how to do this quickly?

If it needs a URL I’ll by one.

Reporting-MTA: dns; googlemail.comReceived-From-MTA: dns; redacted@gmail.comArrival-Date: Thu, 26 Oct 2023 19:41:28 -0700 (PDT)X-Original-Message-ID: <>Final-Recipient: rfc822; redacted@tmomail.netAction: failedStatus: 4.1.0Remote-MTA: dns; (, the server for the domain smtp; 452 4.1.0 <> server temporarily unavailable AUP#MXRTLast-Attempt-Date: Sun, 29 Oct 2023 20:57:20 -0700 (PDT)


Badge +1

According to this answer, use of certain words in the message can trigger SPAM-filtering (which this looks like).

In that answer, @HeavenM , Community Manager, says:

… Are you sending these messages from your personal email address or from an automated email service? Does the email that you are sending from include words like admin, info, alert, test, contactus, or sales? (This is not a complete list of words in the email address that are filtered but gives you an idea.) The message route is not designed for ANY business messages …


Also, this page defines “Consumer” vs “Non-Consumer” messages. It seems backwards, but “Consumer” messages are the ones people send to themselves or their friends, like right from your phone. “Non-Consumer” messages are the ones businesses send, such as when you get an authentication code from your bank or a reminder from your scouting organization, etc - anything that’s sending for a business or organizational purpose. “Non-Consumer” messages have to be set up with TMO or a messaging service.

Beyond that, regular messages are supposed to work as long as they don’t meet the SPAM criteria.

My home security system sends my T Mobile phone text messages, via its gmail account to <MyPhoneNbr>, to warn of intrusions.  The security system’s SMTP configuration is below

This has failed since Sept 14, 2023 (error 550 5.1.1), around Oct 2nd the error changed to 452 4.1.0.

I have logged into the “From email:” gmail account and manually sent a simple test message (Subject: “Test”; Body “Test”, no attachments), to <MyPhoneNbr> and its delivery failed as well.  So SPAM does not appear to be the issue.

Another thread said that the system was archaic and to find another way to contact people.  However, the only published way to send text messages is via

Hopefully someone from T Mobile will resolve this, as many health related services rely upon text messages to contact their clients.

Badge +1

@TooOld said: 

I have logged into the “From email:” gmail account and manually sent a simple test message (Subject: “Test”; Body “Test”, no attachments), to <MyPhoneNbr> and its delivery failed as well.  So SPAM does not appear to be the issue.


Anything sent from a mail account to the address goes through TMO’s SPAM filters. If you get a failed delivery message, you will see AUP#<something> in the failure message. AUP stands for “Acceptable Use Policy” - which means it was SPAM-filtered.


Also, TMO’s 3rd-party SPAM-filtering service decides when and if a particular mail service is blocked. So, one day it might be gmail, the next it might be icloud, or anything else. And, the reasons vary: maybe something in the text, something in the header, too many messages being sent from a particular service (total, not just the ones you’re sending to yourself), or whatever else they have configured.

I’ve been working with this for on-call messages from work for over 5 years. I’ll fix something to avoid the filters, then it’ll stop working again. There used to be a great TMO person who would help me determine what was happening. However, they replied to my last message (“server temporarily unavailable”, “AUP#MXRT”) that they were “leaving due to severance”, so they can’t help anymore. 😞

I totally empathize with your frustration as I have no other method for receiving on-call messages (unless I buy myself an actual pager, and my company has no plans to pay for such service).

I’ve looked into messaging services that can do this as explained in TMO’s Non-Consumer information, and they’re HUGELY expensive. The cheapest versions use random numbers, which doesn’t help with your and my situations. We’d have to pay for a “vanity” number, so you and I get notified correctly of our messages, and that’s even more expensive.


I have since found an incredibly cheap, reliable, and easy to use alternative for use by my home security system.  When it detected an intrusion it would send an email to <myphone#> 


I now use the pushover app ($5 lifetime license, over ¾ million users).  I now send email to <myphones_pushoverid>, which results in a notification (not SMS) to my phone.  It sends both text and images.

This thread shows how it can be done.  They show a complex, full-featured way, but the simple method above works just fine.


I have the same issue. I noticed time-sensitive notifications were not being delivered yesterday.

I sent multiple test messages to my, and none were delivered. Test messages were cc’d to a normal email account, and those were all delivered quickly.

Today I found two of the messages were delivered as text messages, approximately 16 hours after they were sent initially.

No errors are reported when sending to