Hi,

The 50X error normally occurs when the PHP service is not working, due to some reason.

If any of the utility of Webuzo gives you 50X error on opening it, than you will have to restart the webuzo service to resolve it. The command for the same is:
service webuzo restart

If you face the 50X error on your websites than you will have to re-start the PHP-FPM service of from the services page of Webuzo. You can refer to the below guide for the same:
http://webuzo.com/wiki/Restart_services

If you still face the issue, you can open a support ticket with your server root details here and we shall look into the same:
https://www.softaculous.com/support/