Went to at&t to get a new sim card the other day. They gave me a new one and before I left the store I got the message no sim. I went to the Apple store the next day and they swapped phones. I got a new phone. So far it has been 1 full day. But, they Genius said it is a known issue to him and it seems it is a flaw in the design of the sim tray. But, who really knows. I do not hear apple saying anything on this issue. But, for me 1 more time it appears I will just get a refund and get something else.