Ursprünglicher Beitrag von: Minho ,
What error message are you getting from iTunes? In the meantime, I would try another Lightning cable and possibly another computer if you have access to one. Also, remove the SIM card and clean it with isopropyl alcohol (rubbing alcohol will do but if you have higher grade, then use that). Once it's dry, re-insert it. If that doesn't work, I would wait a while, perhaps there is a problem with the connection to the activation server. Maybe re-start your computer or network connection.