'Error joining multiplayer session'

[Nuukov]

Hey all. Me and my friend where enjoying a nice AI game of Civ 5, then I had to go for a while, but later on when I'm back and when he was available, we wanted to continue. Then all of a sudden it says 'Error joining multiplayer session'.
Nothing had changed since we last played. And we can't even join normal internet mulitplayer games.

Anyone had this before and knows what to do, or any idea what has happened?
(BTW we did try things like restarting our computers, routers, and disabling the firewall etc, no luck)

 

[Malkiot]

Just happened to me after installing BNW.

 

[Suna]

Same problem here.. Since i installed BNW i am unable to join -or host- a multiplayer game. It just says "Error joining multiplayer session'

I never had this problem with Civ5 vanilla or G&K