I can't join my friends' games anymore in ad hoc while I'm in college.

Also, I can have access to one of my friends' ad hoc lobbies, but I can't join because he didn't updated (I think). I still can't join my other friends' games, though.

What can I do?

Oh, and guys, please don't tell me it's a internet problem. This is ad-hoc, not WiFi.