Cross Plattform Dont Work

Hey Guys,
I wanted to play with my friend together.
I got the Steam Version, he got the Microsoft Store Version.
Last weekend we were able to play together without any problems.
Today nothing is working out. When we try to join each other the game says “Error: Unknown Error”.
Yea… very helpfull. We can join others lobbies. And others can join my lobby. We dont know exactly if others can join my friends lobby, because no random people joined his open game. The curious thing is, he could join others, so why can’t he join me or otherwise i cant join him if i can join other peoples game.

Greetings and thanks for help.

Exact the same problem for my friend and me. A few days ago everything did work well. Last time we played before Patch. Today we could not join each other Lobby. We changed nothing. It ist maybe a problem with the Patch?
Fix it or tell how to fix pls