Well I am trying to figure that out or get it to work at the moment as well.
My setup comprises OpenLDAP with LDAP Account Manager as Frontend and a DOVECOT_MASTER_USER and PASSWORD on the mailcow site. My idea is to extend the LDAP server with misc.ldif schema and be able to setup mail-accounts from LDAP with the dovecot master.
I was able to let the LDAP server try to authenticate, but mailcow does not allow authentication with the dovecot master or any other account with my settings so far.
I think I will open another thread to layout the setup in detail…