**UPDATE 10/14** Apple has disabled Game Center app friend invites on ALL VERSIONS OF OSX (10.8.5 AND NEWER). This means that you can only play multiplayer games with existing Game Center friends. We've reached out to Apple regarding this issue and will update this post when we hear back from them.
I cannot view or join Game Center enabled MP games on 10.11 (MAS ONLY).
This is effecting the following MAS games:
Command & Conquer: Generals Deluxe
You will need to be invited by players who are running OSX 10.9 or 10.10 to play multiplayer.
There is also an issue with random crashing at the beginning of these games due to Game Center connection issues.
As of right now, we do not have a solution and cannot replicate the issue here. In the meantime, please log out of your Game Center and AppStore accounts and disconnect your internet connection to relaunch the game.
We've logged this issue with Apple and are awaiting an update from them to resolve it. Please subscribe to this article to be notified of any updates.