History has been repeating itself for a year now: Apple’s servers are overwhelmed by too many people wanting to activate their gifts. Users on Twitter and Reddit have already started complaining about this. Not only are they unable to activate new iPhones, but they can also enter iMessage / FaceTime.
Last year, Apple’s Twitter support page admitted that users were having trouble setting up a new device via iCloud. The same thing is happening this year. This situation will be resolved only over time, so American users who are faced with a problem can only wait.