"Match Not Joinable" [84002S:62007S:-5974 162830:393220Q]

TPM and SecureBoot are enabled. Game launches just fine and connects to online services during loadup.

Basically, everything seems to be working properly until I hit "start" at the bottom left of the lobby screen with my kitted out dude standing there. It counts for a few seconds like it's trying to connect, then I hear a sound and my dude stands up and the countdown at the bottom left vanishes like it's gonna connect to the match.

It never does, and after a couple moments the "start" button at the bottom left shows back up. I've tried using the 'server browser' to find games too. Occasionally it will show a thing at the top middle of my screen saying I'm in queue for the server, but it never connects that way either. Sometimes I tell it to connect to a server and it just plain acts like I haven't clicked the connect button and literally nothing happens at all.

The error listed in the title is the only error I've ever seen, and it only sometimes happens when trying to join a multiplayer match via the lobby/matchmaking "Start" button.