MySQL login named xxx is already owned by virtual server

I’m trying to activate the mysql feature for a virtual server and get this message

A MySQL login named xxx is already owned by virtual server yyy.com

When I go to yyy.com -> Edit users, I don’t see this user xxx When I go to Webmin -> Servers -> Mysql -> Users permissions, I don’t see this user neither

What am I missing? Can I choose the mysql login myself?

The virtual servers used to all come from cpanel backups, that I have now merged, and my current structure is one parent virtual servers with many sub-servers.

I’m using last virtualmin on ubuntu 16.04
Thanks

Any idea? This happened on every single server I’ve moved from cpanel to virtualmin.