Can you link me to another thread where this is being discussed? I don't visit the forums frequently but my wife has been complaining about not getting notifications for texts recently. I figured it was just her missing them. So I'm curious to hear if others are having the same issue.
I don't have links, but I had this exact issue. I'd lost nearly ~30 messages/week in some group chats.
iPhone 6S Plus on iOS 14.2 w/ AT&T= not receiving other MMS group messages and "failed delivery" of my messages
iPhone 12 Pro on iOS 14.2 w/ its bundled, preinstalled AT&T SIM =
not receiving other MMS group messages and
"failed delivery" of my messages
Nothing changed!
Exact same problem, two phones, two SIMs. The in-store AT&T rep, crazily, told me, "Well, see, the 6S is an old phone. Sometimes they don't get messages. Good thing you're getting a new phone."
Useless.
Until I called AT&T—their phone support is
miles better than their stores
—and they stated "Ah, while you did activate it, the activation hasn't completed on our end. I need to force the activation to go through and this should fix the issue."
AT&T "forced the activation" (yeah, I don't know what that means, either, nor why it was stuck) and, bam, I've now gotten 100% of group chat messages and haven't lost one since that AT&T call.