This error code is a very generic output to a KMS client having problems activating. To view your output, run slmgr.vbs –ato
When troubleshooting this problem, we checked the following details – if any were a problem, they would generate this error code:
And the last one was the problem we hit: Our KMS server was Windows Server 2008 R2, just as the KMS clients. We’d crossed the threshold of 5 servers. But they still would not activate. The problem was that there are different license “channels” for Windows Server. They are described here: http://technet.microsoft.com/en-us/library/ff793411.aspx
Our servers which were having problems activating were all Windows Server 2008 R2 Datacenter Edition, and we had a “B Channel” KMS license installed on the KMS server.
We followed these steps on the KMS server to install the correct channel license:
After doing the above, we ran slmgr -ato on the Windows Server 2008 R2 Datacenter Edition servers. Note that “Channel C” is able to active all lower level channels.