Halo 4 players are reporting problems connecting to the game's multiplayer servers. Users on the Halo Waypoint forum are apparently encountering a "server unavailable" error when attempting to connect to multiplayer matches.
The Xbox Live status page reflected the issue earlier today, though at the time of this writing it indicates that all services are up and running. We were able to play two online matches without a hitch, but users are still reporting problems, including being unable to join games, play with friends or access their unlocked loadouts.
Microsoft is aware of the issue, and Xbox Live guru Major Nelson informs Joystiq that the Halo team is working to resolve it.