Error message:
When I add the domain controller, I get an error "The given servers are not operational".
Possible cause:
Domain Controllers (DCs) are down.
The firewall has been enabled, and port 389 is closed.
The network is busy.
Solution:
Ping to check if the domain controller is operational.
Check the firewall for inbound and outbound rules.
Rectify any problems with the domain controller.