I've tried everything and nothing has worked. With my new unlocked ATT tilt (HTC Kaiser) 8925, I can receive an SMS message OK but cannot send. This phone was unlocked by the ATT. My provider is Tmobile, and sms settings are correct (+2063130004). I've tried sending with this sim card on another phone and it works. I've tried other sim cards for the ATT tilt and still cannot send with the phone but can receive just fine. I've done a hard reboot on the phone and still nothing. The phone has enough memory and signal to normally send but goes directly into the outbox coming up with a message "your text message cannot be sent". I've tried everything and have looked on all forums and still nothing. This phone also has an issue with connecting to activesync. Please help.