People trying to connect to WAN-based (Internet) servers, may not be able to pass the loading screen, resulting in a need to forcebly shutdown the game.
To try and bypass this problem, you can try to use the Direct Connect option, altough in some cases it still might not work.
LAN-based servers are not being affected at the moment.
We're working to solve this and will post an update ASAP.
Thank you in advance for you consideration.
The Shrooms Team