If you're on the Discord you can read the troubleshooting section in the server guide (very top channel). You don't need a verified account to read, the verified account is only for chatting.

Try verifying the integrity of the files. In Steam you right click and go to the properties. Go to files section and click the verify option. Steam will make sure you don't have any corrupt files and that you have everything you are meant to. This would be a good first step. After that there is the option to uninstall and reinstall the game in Steam.

If you are on Windows and have access to an admin, open command prompt as administrator and run: sfc /scannow

Please google what commands do before running them just because a stranger online said to do it. It is always good to check first.