Last night I had two instances where the match making lobby found all the people and the match deploy timer went all the way down. But when it tried loading the game, it would bring up the loading screen with game tips, then boot me back to the main menu. No error messages from either time it happened. The two times this happened weren’t consecutive though, I remember getting into a match after the first time it happened to me. But after one or maybe two matches after, it happened again. So I backed out of Halo 5 and went to my network settings. It’s said both my network and multiplayer connection were good. I also kept losing connection to Xbox Live party chats all day too.
Edit: I guess it only happened once last night, according to my service record at least.