Iphone 4 says "connecting..." for a few seconds then goes straight to "Connection lost"

Just yesterday it was working fine, but this morning facetime has been not connecting.

It connects for a few seconds, and then it goes straight to Connection Lost.

i have tried calling the person a bunch of times and it does the same thing. They have done the same, and apparently their iphone is doing the same thing, too.

Is there something wrong inside my phone? I/m sure its my phone because my connection is full and working for every other app. is there any other method i can do? i have tried resetting my phone, wifi, and my facetime. Please help!

Thank you.