I got a little messy situation on my fresh Virtualmin setup, I imported an existing domain and somehow the postfix group was renamed into the group of the domain owner. This basically led the postfix user to be listed in the domain email users, with the ability of the user to delete it along with the home directory of postfix, /var/spool/postfix… not very nice
So now I basically tried to fix the situation, renamed the group to postfix again, created a new group for the domain admin etc.
Now there is a problem: Virtualmin still thinks the group is GID 104, but it should be 1004. Here the error while validating: