I've been trying to join a party, or invite someone to my party, and it's just completely messing up. It will not allow me or my friends to join a party, to go on Nazi Zombies or multiplayer! And it's getting extremely annoying after trying everything we can possibly do! Its taking the complete p******. I, and many others who have the same problem. It ruins the game all together. I am on NAT Type 2, and I am on a BT internet connection.
It says: "Game session unaviable" or "Unable to join game session" - something along these lines. Somebody HELP!
oh right, thank you very much for you help :-) we shall try again soon. thanks again!