A work around to this is use slmgr.vbs to manual enter the key on command line/powershell, run as administrator.
slmgr.vbs -ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx
Once the key is in the system, instead of using the wizard to activate it automatically which you have tried thousand of times and never work, it is time to use the old fashion way. Phone activation!
Now use this on CMD/Powershell:
What happens now is the activation wizard will pop up and ask you to select country, click next and boom there's your confirmation ID.
Ring up Microsoft 0800 free call number on the screen, enter them the generated "Installation ID".
Click "Enter confirmation ID" Once entered, the computer on the phone will then tell you the numbers to put in activation screen next.
Job done :) Windows is now activated.
slmgr.vbs /dlv - Display information of current license status
slmgr.vbs /upk - To uninstall windows product key
slmgr /upk <Activation ID> - Use this to uninstall the auto generated windows product key, so you can install your own key.