I recently got an iPhone 3GS without a SIM card. I upgraded it to iOS 6 from 5.1.1. However, the phone is stuck on "Activation error" after successfully connecting to my WiFi. The screen says:
Activation request could not be completed. If the problem persists, please contact customer care.
If connected to iTunes 11, iTunes says:
We're sorry, we are unable to continue with your activation at this time.
Resetting the phone doesn't work. Anybody has any ideas, besides contacting customer care?
Edit: The problem was solved by inserting a valid SIM card.