Question

Digits SMS from MVNO


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I cannot receive SMS messages from friends who use MVNO service providers (Mint, Tello, USMobile). I have gotten the most ridiculous replies from engineering regarding this issue. Upon further testing I found that if the MVNO phone sends an SMS to the phantom phone number associated with my digits SIM it goes through, however, if a customer of another cell provider send an SMS to that phantom number it does not go through. 

It seems the SMS messages coming from the MVNOs are not entering the digits system.

I found the following 5 year old post at:
 https://www.reddit.com/r/tmobile/comments/5mzq1v/digits_beta_breaking_inbound_mvno_sms/

which makes it seem that this is a really old issue. Is there a solution?

I reported this issue to DIGITS advanced technical support and it's been relayed across to engineers. However, I'm curious to know if any other beta testers are hitting the issue.

Scenario:

  • I'm on T-Mobile Postpaid with 3 lines associated with DIGITS and my gf's line that isn't.

  • My friend is on Ultra Mobile (A T-Mobile MVNO)

  • Friend gets all my text messages from my phones native or digits app.

  • I don't get his texts on any of my lines associated with DIGITS on either phone or app.

  • My gf on my account (but not digits) can get his texts. So can other t-mo postpaid, at&t, and google voice customers.

  • Removing lines from DIGITS doesn't solve the problem, texts still don't make it to those numbers.

Other things verified with my friend. Texts were sent using Textra or his stock android SMS app on his phone. No errors shown for him when texting me. His SMSC (SMS service center) number is set the same as T-Mobile's. We ruled out any chance of these being caught in Whisperpush or iMessage hell. My one number I've had since 2002, the others were new within the past month. Tested with latest IOS and BB10 on my end, even swapped the sims.

In conclusion, it's a weird bug. Support seems to be taking it seriously and stuff like this is to be expected in a beta program.

I theorize that Ultra Mobile has some weird routing agreement for their SMS with T-Mobile that DIGITS updates and breaks the internal network routing for. I'd guess that to be the case because they provide international messaging under the market rate (bridging the messages to IP? Think VOIP bridge numbers for calling cheap internationally). So yeah, sort of like how local mailserver delivery can be broken for servers on a LAN with a broken DNS, but work for everyone else on the public internet. But I don't know anything about T-Mobile's internal network so this is my intuition and speculation. :)

EDIT: Chatted again and relayed more information across. It's confirmed there's an open bug # in the system. Support was also able to confirm my intuition was at least partially correct. Flipping on DIGITS moves lines off traditional SMSC to a new type of server. Presumably, this is so they can do things like syncing message history.


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