unfortunately are out of the office, sorry for the delay.
Zentyal Core version 2.2.11 (very old, ubuntu 10.04)
At the moment I do not have access to the NS, but I remember that Zentyal has no admin user.
Then I have other difficulties:
1) Zentyal LDAP runs without TLS / SSL and sssd not allow authentication
2) In Zentyal, the groups have an email address and the members of the groups are automatically routed.
The first point I resolved with LDAP over SSL, it is cumbersome but you can do.
For the second point I'm looking for a solution ...