When I set up my new ISPConfig 3 server I migrated all the mail clients and web sites from an existing server that I am replacing.
I was logged in as admin and created all the mail zones, aliases, forwards etc... under my own client ID.
I then decided that some of my customers would benefit from their own control panel login so created some clients, went into the respective mail zones and sites and changed the client ID.
When I then log into ISPConfig using that client ID I can see the mail zone and web sites allocated to that client but none of the defined mailboxes, aliases, forwards etc...
I have fixed the problem with phpmyadmin by manually adjusting the user and group id on the forwarding table but wondered if this is intended behaviour ?