Fixing server downtime; File Manager and PHPMYADMIN fixes

I'm looking for a server expert to look into my server. My website is constantly down after a guy here in Freelancer migrated some websites to the server. I believe there is misconfiguration on the server which is affecting all the services running on it. I need someone with excellent knowledge of server administration to run a check on the server configuration and fix any issue on it and also resolve the problem with my constant website downtime, resolve missing file manager and phpmyadmin.

From the server I am constantly receiving the following email notification on daily basis. Please see below