virtualmin scheduled backups not backing up mysql

i have the backup running fine except one thing ...it does not make a backup of the mysql database correctly ...it creates a .sql file that 4KB big .... i've seen this happen in phpmyadmin when i have tried to zip an export of a database that is large it sends a blank file with correct name and everything but no data ... can you please advise on how to fix this?

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i just checked another virtual server back up ..... in that one there is no mysql file at all so its not getting the database in the backup

please advise

What does that 4kb SQL file contain exactly? It might be some useful error message indicating when the DB dump failed ..