MySQL -Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock

Hi Team,
2 days before ISPConfig server was working fine, aftersometime the mysql service was not running it showing "
MySQL -Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock
"

We also checked if socket file is present in another location or not. no file is present in another location.
If we reinstall mysql it will delete our existing db or it will install only config file.

or else is there any way resolve this error.

We follow The procedure for installing ISPConfig in ubuntu 16.04

 

Is mysql running on that host?
Try

Code:

systemctl --state=failed