This is killing me. It has been 24hrs of red exclamation marks every time I send picture messages. Yet, other people in my area with the iPhone are not having issues. I've done the carrier update, soft reset, hard reset, full restore, sim card in/out, called AT&T yesterday to add/remove my messaging package. I called today and they tell me I need to wait 24hrs. Oh great.
Is there anything else I can try?
#1, try to confirm with whoever youre sending MMS to that the MMS isnt going through. I was still getting the red ! for several hours even though my pictures WERE going through.
#2, Are you jailbroken? If so, remove ANY carrier images, text, etc and reset back to the AT&T logo.
#3, Call AT&T and have them remove all of your plans/features, add them back and finally, resync your account into their system. This is what FINALLY, after 7-8 hours, fixed mine.