Is your KMS client set to the default auto-discovery or is it set to a specific KMS host?
By default, your KMS clients are set to automatically discover the Service (SRV) record for the KMS host from DNS. If the SRV record has been published and can be located, the KMS client will request activation from the KMS Host.
In troubleshooting KMS activation issues, setting the KMS Host may be used to determine if there is an issue with name resolution. Using the following slmgr commands (from an elevated command prompt), you can modify the setting:
- Set the KMS Host – cscript.exe slmgr.vbs /skms <Name:Port or IP Address of desired KMS Host>
- Reset to Default of AutoDetect – cscript.exe slmgr.vbs /ckms
Note – Slmgr.vbs commands can be run remotely as well. See TechNet article listed in references.
Here is an example of setting a KMS client to use a specific KMS Host with an IP Address of 184.108.40.206:
The value has been set in the registry as well.
Here is an example of returning the KMS client to auto-discovery.
The value has been removed from the registry.
If you are able to activate using the /SKMS switch, then your activation issue may lie with name resolution issues or the actual SRV record.
“Slmgr.vbs Options for Volume Activation” – http://technet.microsoft.com/en-us/library/dn502540.aspx
“Section: Running Slmgr.vbs Remotely” – http://technet.microsoft.com/en-us/library/cc303280.aspx#_Running_Slmgr.vbs_Remotely
“How to Troubleshoot Key Management Service (KMS)” – http://technet.microsoft.com/en-us/library/ee939272.aspx