Resolved -
Our serivce provider Twilio has informed us that the issue has been resolved by AT&T on 4/1. You should no longer see any delivery issues for incoming messages from AT&T numbers.
Apr 1, 19:51 PDT
Identified -
We are currently in receipt of a notification from our SMS service provider that some incoming SMS messages from AT&T network will experience delivery failures. Twilio is currently coordinating with AT&T to resolve the issue and resolution is likely to take some time. We will post updates here. https://status.twilio.com/incidents/yj1zs05p8f9c
Mar 31, 00:52 PDT