Got referred by Microsoft. All servers have been down for over a week.
Please use this thread to track the current issues
https://www.halowaypoint.com/en-us/forums/36cecc379ca14abd918029d359551927/topics/halo-4-servers-down/ee31a9a5-5857-42ea-a899-3ae1b7bba90e/posts?page=1