If my 4s drops to edge it won't connect to iTunes, the password.... Are your cap locks on and are you putting the capitol letters correct? I get that one wrong a lot not many sites make you have atleast 1 capitol letter and 1 lower case.
You can sometimes do a reset and get your 3G signal back too.
Sent from my 32GB iPhone 4s on iOS 5.1!
Only thing iPhone is missing is an expandable memory port! Come on Apple give us a microSD port already!
Reboot your device by holding done the Sleep/Wake and the Home buttons down at the same time–keep holding them both down until you see the Apple logo. Ignore the "Slide to power off..." prompt and ignore the black (blank) screen.
This thing is strange. I did what you said, signed out, then back in.That went through fine. I even downloaded a free app to test it.
But, when I finished that I tried to update my apps , it asked me to sign in again, I did, then is shows cannot connect to iTunes store.
General, reset, Erase all content and settings. THIS WILL TAKE YOUR DEVICE BACK TO LIKE IT WAS OUT OF THE BOX!
All caps so you'd realize this is a last ditch effort. All data will be lost, but if you want to start all over, this is a way.