Hi @Merle,
You can find out more information about the error by right clicking anywhere on the screen when the screen is stuck, which will open the console. Then, at the top of the window that will pop up, click on ‘Console’ which will display any error messages and point you in the right direction.
You can find our documentation on online troubleshooting here, and it is always worth bookmarking @wakecarter’s amazing crib sheet 
Hope these help!
Kim