I might have an idea, sometimes that (rarely) randomly happens to me. Its a real pain lol, but i think i have the solution,

If u have a windows (only version i have with experience ) press Ctrl+Alt+Del ONCE! and delete all things except explorer and the actual game

That usually (if not solves the problem). Or sometimes there is just too much memory taken up by your programs.

But this never happened to me when i banned somebody, Im using 1.23 so it might be different. It was just random

Hope this helps

Cyaz