For the past couple of weeks my friends and I have been having problems joining each others multi-player lobbies, we also have problems staying together post game. It usually results with the whole party resetting, re-loading the game and or re-booting our systems, sometimes working but more often then not we have a member not able to connect to the pre-game lobby. We also heard that some of the new apps in the preview program were to blame so we all un-installed them and re-booted, it seemed to help a bit but the same problems came back later on and in following days with many of our friends. Why does every update seem to mess with this game?
MCC wreaks havoc on my party system as well. Tried to play today and both of us were continually disconnected after a few minutes or told that we could not connect at all. After completely resetting systems it worked for a few minutes, but then we would get disconnected and stuck in the same spot. We eventually just gave up playing, but hey, we got one match in at least.
I was having this problem as well. If you’re part of the XBox Preview Program, the latest update broke MM with MCC. Go to your apps and uninstall the wireless display app, then restart your box. That should fix it.