Server Error (500)

am unable to access my saver, the page it use to give me is showing: “Server Error (500)” i tried to repeat an upgrade process which i had done some days ago but i upgrade didnt complete, this is what i got: ‘Can\‘t connect to local MySQL server through socket \’/var/lib/mysql/mysql.sock\’ (111 “Connection refused”)’). None of my websites is currently working.
PLEASE HELP.

Have you updated the MariaDB version on your server?