The host server itself must activate once with Microsoft (via internet or phone). Once activated, it is ready to serve your local clients. Troubleshooting Common KMS Issues

This is the most common error. It simply means the KMS count is too low . You need at least 5 unique Office installations to contact the server before it starts "granting" activations.

cscript ospp.vbs /sethost:kms.domain.local

Control all activations from a single point.