You may need to call back to ATT tech support. You will need to check your TCP and mobile network settings. You may also need to se if they will send the servicebooks to your phone. I begin to think I should have backed up all the stuff from ATT I wiped from my 8310 when I switched it to Tmo. Otherwise, you can try re-installing the ATT branded 4.5 OS. That may give you the service books and settings you need for MMS/SMS, you may still need to manually enter the TCP settings, though.