My spouse and I have been playing DOS2 together through LAN for weeks, without a problem. But suddenly she can't play anymore.
When she starts the game, all the options in the main menu are greyed out, except for "Profile", "Credits" and "Quit game". When she clicks on "Profile", the only option she can click is "Create". When she does so, she can fill in a name, then click "OK", but then, nothing changes. The "Profile" dialog disappears, but the main menu is in the same state as before.
She has tried logging in and out of Steam, restarting her MacBook, using the "Verify local file integrity" option in Steam, and installing the latest Catalina MacOS update (as of 5 minutes before this post). In all cases, she can launch the game but the main menu is always in this state.
(I am posting for her as she is uncomfortable writing in English.)