I work for a trucking company, and we use e-mail to SMS to send out dispatch messages to our drivers for load information. Drivers can then reply to those messages to have conversations with dispatchers who operate via e-mail.
This has been working for years; however, as of 3/26/2018, it seems our entire domain has been blocked by T-Mobile servers. E-mails sent to firstname.lastname@example.org are rejected with 550 errors. I have tried sending as plain text, e-mail, short, long, with picture, and just about every way I can think of, but it's always blocked. Messages sent to all other mobile carriers are still going through just fine.
I have tried calling support, but no lower-level techs seem to even understand what E-mail to SMS is, and they just exhaustively try things that are specific to one individual phone. They supposedly escalate the issue, but we never hear back. I am desperately searching for someone within T-Mobile who can actually tell me why my domain is suddenly being blocked. This functionality is critical for our drivers to do their jobs; I'd prefer my answer to those drivers not be "sorry, find another carrier" as they keep asking us why their messages are failing while all the non T-Mobile users are moving along just fine.
Best answer by tmo_chris
I wanted to pop in here and update the correct answer as the rules and guidelines on automated SMS traffic have changed.
- Per Cellular Telecommunications and Internet Association (CTIA) Industry guidelines, Intercarrier guidelines and T-Mobile's own Terms and Conditions of Service, automated commercial SMS traffic routing on any network should use short codes.
- Repetitive mass texts over 10-digit texting are forbidden by CTIA carriers, including T-Mobile. Continued SMS abuse can result in subscriber number being permanently blocked not only by T-Mobile, but also by other carriers, which is outside of T-Mobile control.
- Commercial trafficking is only allowed through short code, and not through long code (10-digit numbers) and a customer must opt in to receive content.
- Third-party services can send bulk messages, but such vendors are unaffiliated with T-Mobile.
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