I was getting ready to make a phone call ,i switched on the phone mode and hit my favorites key. the phoned looked like it was trying to make the connection,but wasn't going through.i hit the end call key.i tried this several times and still no connection. i noticed in the top left corner i had full signal strength,but a funny thing the AT&T logo was gone. i decided to reboot the phone.after rebooting the logo was back and i was able to use my phone.Has this happened to anyone else?