I just bought a 32GB 4S from Ebay. I currently use straight talk on my 4 and was thinking it would be a simple SIM swap and be done. I keep getting "iPhone could not be activated because the activation server is temporarily unavailable.". I even tried my old AT&T SIM and a working T-Mobile SIM. They all do the same thing. I have also restored 4 times, 3 of which using DFU mode. I have called AT&T and they have verified the phone is not blacklisted and that is should be unlocked. Any ideas. I have an appointment today at the Apple store but am hoping to save a trip. Thanks.