Intermittent failure to receive SMS and MMS messages I noticed an issue in mid December where a few messages in a row that were sent in a group MMS were never received on my phone. A few days ago, I had the same issue with an SMS message sent to me. There may have been other instances as well that I'm unaware of. In December, my default messaging app was QKSMS. In the instance a few days ago, my default SMS/MMS app was Signal.
I'm using an Asus Zenfone 6 on Wing's AT&amp;T network (for those don't know, this essentially means Wing bought AT&amp;T contracts in bulk and is reselling them individually).
I don't know of any issues with outgoing messages. The intermittent nature of this problem makes it difficult to troubleshoot. What steps can I take to ensure I don't lose any incoming MMS or SMS messages in the future?
In my case, the issue with the two non-stock messaging apps was the battery settings. Android was throttling the apps when they weren't in active use to save on battery. For whatever reason, incoming text messages would be directed to the apps but the apps would never wake up and the message would fall into a black hole. The stock messaging app was set to never be throttled in the Android battery settings. Changing Signal to also never be throttled seems to have resolved the problem. This is a known issue for Signal: https://support.signal.org/hc/en-us/articles/360027913252-Troubleshoot-receiving-messages