Problem sending group texts and mms photos, solved

I had an issue with my iPhone 13 Pro (iOS 17.1) unable to receive or send texts to a group when one member was not on iMessage. The texts went as text messages but would not group together. Also was unable to send photos to android phones with MMS Messaging (all settings were correct and turned on). I got an error message to turn on MMS Messaging even though it was on.

After 90 minutes on the phone with AT&T and then another 45 minutes with Apple (including a total wipe and reinstall of the phone), it still wouldn't work and I was elevated to a tech who provided the fix. Reset all settings. The fix took 5 minutes.

Go to: Settings > General > Transfer or Reset iPhone (near bottom) > Reset > Reset all settings.

This fixed the problem. You just have to re-enter things like wifi passwords and other settings that get erased.

I hope it saves you the 2.5 hours I spent fixing this!