Q: The activation server is temporarily unavailable?

I have the same problem after ugrading from ios 4 to ios 6.1 (activation server unavailable).

i have the same problem, can someone help me?

Generally this is a sign that the iPhone had previously been

hacked/modified/jailbroken and the update relocked it to the

original wireless carrier. If this is the case, only that wireless

carrier can unlock your iPhone. You must contact them to see

if they offer unlocking and if you qualify.

 

Where did you acquire this iPhone?

What wireless carrier did you use before this problem?

 

Does the app Cydia appear on your iPhone?

What does it say when you look at Settings=>General=>About=>Carrier?

 

Unauthorized modification of iOS

http://support.apple.com/kb/HT3743

Vodaphone agreed to unlock my iPhone 4s which was my friends contract phone but I'm getting that same message

And its sometimes saying invalid sim, so I'm stuck