Some Halo 4 players have been unable to connect to the game's servers for the last three days.
Players believe problems started around the 26th November, when the latest set of Spartan Ops missions were released.
Players seem to be stuck in the game's fallback servers, preventing them from connecting to the main servers. This is having the knock-on effect of temporarily resetting in-game ranks and loadouts. Experience points can be earned by at a greatly reduced rate.
A member of the Halo Waypoint forum team posted to acknowledge the issue and confirm it was being looked into it.
There are a few hundred players who have been unable to connect to our servers since yesterday," reads the post. "We're investigating now and hope to have an update soon.
343 wants players to help it sort the problem by providing information such as Gamertag and region in this thread.
The Halo Waypoint Twitter account has been busy over the last day or so addressing multiple complaints. We're actively investigating the server issues," is its standard reply. "Apologies for the inconvenience.