I have the Primary server sitting on a DMZ, and users will be coming
from two different LANs throu a firewall.
All ports defined in documentation is opened in the firewall.

Testing with PCs from one of the LANs.
Workstations registers fine, remotecontroll and so working.
But when trying to login with a user the client says:
"Unable to log into the network because the login credentials or the
server certificate is incorrect"

When loging in with the same user, from the server, it works fine.
But from the other LAN, not.

User source is an eDirectory, standing on the same LAN as PC and
Admins are defined from that User Source, and it works fine loigging
in to ZCC with that, both from DMZ and production-LAN.