I have had the same problem on Windows. Restarting the server fixed it for me.
I'm using dedicated server.

Some other problems (also dedicated server):
- Disabling crossplay makes it impossible to join the game from outside LAN
- Also, when using crossplay, LAN connections to server are not possible, I have to use loopback connection (that is, connecting to my server using my external IP) if I want to connect to my own server
- Crossplay makes players frequently get kicked from server for connection timeouts, practically unplayable for online players. Haven't had any problems with this before the crossplay update