I factory reset my iphone 5

I had abit of trouble with network coverage and as a last resort, factory reset my iphone 5.
When I turn it on now, it goes to the activation screen, tries to connect to to Wi-Fi, does.
Then it says "activating your iphone (it may take a few minutes).
after a few minutes it then says… "Your iphone could not be activated because the activation server is temporarily unavailable. Try connecting your iphone to itunes to activate it."
I try itunes, and the same happens more or less.

What does it say when you connect your iPhone to iTunes ( you probably need an activated sim card)
Is your phone factory unlocked, or with att, tmobile… Etc

I had the same problem with my little sister's iphone 3gs… Then i factory unlock it and i inserted my tmobile sim and it works.

More info would help us find a solution to your problem