MMS only sending to other AT&T phones
I am using both a new AT&T branded Samsung S9 (running Android 8.0 and Samsung Experience 9.0) on the AT&T network and an older Motorola Moto E 2nd gen (Android 5.1) with 4GLTE .
I lost the ability to send MMS messages to non-AT&T phones on Tuesday, September 4 around 9 am.
I can send/receive images from the AT&T Samsung phone to the AT&T Motorola phone, and vice versa.
However, MMS sent from either the Samsung S9 or the Moto E to phones on the Verizon or Sprint networks are mostly not being received, or are being received many hours later.
Advanced messaging is turned off.
I have tried turning on WiFi and turning off WiFi.
All images are under 1MB.
WiFi calling is turned off.
I have rebooted the phone multiple times.
I have added no new apps, nor have I reconfigured the phone in any way.
My phone says it is up-to-date with software.
I have no problem receiving images.
This appears to be an AT&T network issue ?
*update - but unsolved -
Another user in the forum having the same issue says that although AT&T personnel first blamed the SIM card, it now appears to be that their phone is not maintaining the APN settings. I
I set up a new APN settings profile and was able to send MMS to a Verizon phone from the AT&T Samsung phone.
I did not adjust the APN settings on the Motorola. They are all grayed out as if being ignored.