E-mail to SMS being blocked due to suspected SPAM

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I just tried from my email, but I am not the one who normally sends them out. Mine seems to have gone though. I will have our office admin, who normally does send them out, try in the morning, and I will report back to you then. Thank you!

I just tried again and the notification came through!  Thanks a bunch for your help. 

Is there anything else we need to do or alter to get whitelisted?

Thanks again!

sorry, commented on the original thread. 

That seemed to do the trick.  Thanks!

Is there anything in particular that we need to be aware of in the future with regard to filtering and whitelisting?

Thanks again!

Thank you for the detailed information and we do have plans to move most of these messages over to the 10DLC for A2P.  Since you are very knowledgeable in this area do you have any information on when T-Mobile might be implementing support for the A2P/10DLC using 10 digit numbers?  In following the new CTIA guidelines it sounds like they expect all the carriers to be supporting the 10DLC/A2P so I was hoping T-Mobile would be moving towards that before too long.  I know Verizon had a couple dates set for their 10DLC rollout and have moved it back.

I really have to say I appreciate your knowledgeable help and thoughtful responses to my questions, even if it's not what we were hoping, and I understand your considerations.  Best support I've seen from any carrier relating to these topics so thank you and have a great day!

Thanks, Mark

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Yes, 10 digit shortcode is coming soon. It's my understanding that long 10 digit texting codes are in testing that just started and I dont have a completion date. Thanks for asking. I indirectly support that regarding spam over shortcode issues. Thanks!

We're blacklisted, too. What is the best way to make sure our organization is whitelisted? This message thread appears to be the most hopeful information I've found.  Please let me know, and I'm happy to send you whatever information you need.  I appreciate your help!

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Won't know block reason until can review it. Can you please send me a follow through inbox? Thanks.

Hello - same issue here ... emails to txt were going thru no problems until this week and now getting 550 permanent failure for one or more recipients ( rejecting banned content).  Emails are coming from

I have followed you.  Have checked and it seems that SPF is correct as well.

Thanks for help researching the reason for rejects.

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Hi @randyhmiller

Hello neighbor! It was rejecting due to a random generated keyword in the header for ProofPoint scanned messages - had a content match that looked like a domain entry for some recent spam attack that had to be blocked with content match. A few other messages also had random generated message ID's which matched a few other patterns. I have adjusted and messages are passing.

Time for some Hutchins. 😊

Wow - thanks for the quick response!  Definitely in for the Hutchins BBQ ... but you got to get there early or the line is TOO long.

Good afternoon!  We're having this same issue and I was hoping someone could help.  I send a follow request to 'srickar' and it looks like it was accepted, but I'm not able to send a message.  Any ideas how I might get in touch with someone would be greatly appreciated.


Please add me to the list of admins with this problem… our email to SMS has been working fine up until the last month with the same error:

Failed to deliver to ''
SMTP module(domain reports:
message text rejected by
550 permanent failure for one or more recipients (,,,


Multiple calls to support have not been fruitful even after pointing them to posts on this forum.


Please give guidance on how to fix this high priority problem.

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I sent you a PM. Meet you there!