Occasionally mysql goes down

Before i post i had search in forum with same problem seems unique

- Linux Distribution and version used on your server.
Ubuntu Server 14.04.5 lts

- ISPConfig version
ISPConfig version is 3.1.1

PHP
5.5.9

all working just find just Occasionally 1 per month and sometimes more the mysql gos down

Using VPS with 2 Ram

Thanks

 

What do the logs say?

 

thanks for the quick reply
Mysql or Sys to post it in here