I have an iPhone 6 plus (iOS 8.3) and can't send or receive MMS messages. (My iMessaging works with those friends who have iPhone 6s. My MMS messages don't.) Yes, I know it's been asked before. Tried everything: soft reset, factory reset, toggling iMessages on and off, network reset, LTE off, LTE just data... Nothing works. I have AT&T. Anything I can try other than the above? Note: Please don't suggest "Turn off text forwarding." That does not appear in my Messages settings menu. I apologize for asking something asked before, but none of the suggestions I've Googled have worked. Thank you! P.S. I'm able to send MMS texts to myself/receive from myself.