I just found this thread (“Issue with multiplayer…”), where they say:
If that doesn’t resolve, you might make sure you’ve done the Ranked Benchmark Test. You can find this in the Options menu, in lower-right…
Or by clicking the “Ranked” tab of the Multiplayer area, and this will pop up:
And you could also check to make sure you have enabled cross-network play. I don’t know why this one would prevent you from seeing lobbies or playing a match, but it might? I think a friend was unable to see lobbies until he enabled this.
