When using an LDAP installation (e.g. openldap) without using LDAP groups Zammad will reject the LDAP setup completely.
This is not documented on LDAP / Active Directory — Zammad documentation and there is no documentation what to do to create groups for Zammad.
I think the correct approach would be to allow a setup without Groups and setting all users as customers as default.
I should have included the error I get. Sorry.
I just tested it again to look into the developer console and actually did find the problem.
I get the error that Zammad can not find the LDAP groups if I try to use ou=users,dc=example,dc=org but it does work with dc=example,dc=org
In the group assignment wizard Zammad does not even show ou=users as a suggestion.
I did use the admin ldap user so I do not think that this is a permission problem.
We do use OpenLDAP.
But as I did unterstood the error message wrong I agree that this is not a Feature request.