If you see an error like "no tidy :(" then it is likely that the PHP version has been automatically upgraded on the server without re-enabling the php-tidy extension.
The fix is to ping an admin and ask them to check the phprc file on the H2VX server (likely at the path ~/.php/N.M/phprc where N.M is the PHP version like 7.4 or 8.0) and see if it has the line:
extension = tidy.so
If not, edit the phprc file and add it. That should fix it.