How To Activate Windows Server 2016
The activation system in Windows Server 2016 is broken. It fails to activate because the product key is invalid. You can’t enter a product key because the Change Product Key button does nothing. The old SLUI 3 trick also fails.
dism /online /set-edition:ServerStandard /productkey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /accepteula