Error Message: When I add the Domain Controller, I get an error as "Unable to get domain DNS / FLAT name".

Error Message:

When I add the Domain Controller, I get an error as "Unable to get domain DNS / FLAT name". What does it mean?

Possible Cause:

When the ADManager Plus server is unable to communicate with a specific domain or domain controller.

Solution:

1. We need to download the DMZ Port Analyzer from the following link (it is a Free Tool):

   https://www.manageengine.com/products/free-windows-active-directory-tools/free-dmz-port-analyzer.html

   After downloading, run the program and enter the Domain Name/DC Name. The DMZ Port Analyzer will provide the ports to open (in both directions). Once this action is completed, we should be able to add the Domain without any issues.

2. Try using the IP address of the domain controller.
3. Check whether the DC name/IP is pingable.