Hi I have the same problem with my Iphone. In fact my problem is all the time to all numbers I try to send a text. Incoming text is not a problem. I have spent about 4 hours with customer service and At&T technical staff and Apple technical support. I spoke with 9 different people and two were supervisors. The time spent was a waste of time and very frustrating. Nothing was fixed and they basically did not know how to help me. Does anybody know what the solution is? is my IPHONE a defective one?