There was an error connecting to the Apple ID servor.

I can't sign in to Itunes on my computer, neither can I authorize my computer in Itunes or connect into Icloud because I always get the same error message :

There was an error connecting to the Apple ID servor. However, I have no trouble connecting on my Iphone.. I have tried to unistall Itunes on my PC. I have tried to disconnect from my phone and reconnect and still doesnt work. Any help?