Sometimes when deploying computers in our organisation, they don’t see our KMS server and automatically activate (even though they are told to do so via our unattend.xml). 9 times out of 10 it’s the client itself having issues just talking to your KMS server. To check and see if you can contact it, you can perform a DNS lookup for the KMS Host. Open a command prompt window and type in the following:
nslookup -type=srv _vlmcs._tcp.<FQDN>
replacing the <fqdn> with your fully qualified domain name. It will look up the DNS record which the Software Licensing service checks to contact a KMS host. From here you can try and ping the machine using the above DNS entry.
You can also use some other commands on the KMS host to ensure that it is working correctly and accepting clients and activating them. Opening an elevated command prompt window on your host machine you can use the following:
These two commands will show you detailed information about your KMS host machine such as the number of failed/successful activations as well as client counts.