It’s been 2-3 days now where everyone’s default & matchmaking unavailable.
Please use this topic in the mean time https://www.halowaypoint.com/en-us/forums/36cecc379ca14abd918029d359551927/topics/343-response-halo-reach—unavailable-server/845206b5-3974-4d98-870f-d42deea76bed/posts