I only purchased the game a couple of days ago, so i just got a refund for it. Sad to hear this has been an ongoing problem for a long time now on Xbox, and hasnt been fixed or commented on from the game developers. Multiplayer for me is a big part of a racing game. Shame, as it's a fun game.
I’m also having this exact problem. running version 184.108.40.20637 on Xbox series X xbox series X. nat type open. Connection tests all working. all other games work fine online. this happens to me all the time when trying to play in public lobbies. Unable to play multiplayer at all. whts the update on this? Really big bug.