I am an Independent Advisor here to help. I know that this situation is frustrating. This type of error is cause when Windows was activated using a Volume License Key. In order to continue using this key the computer needs to be connected to a corporate server so that the KMS server can update the lease on the key for that computer.
To resolve this issue you will need to move the computer out of the volume licensing channel as follows
Open an elevated command prompt (type cmd.exe into the Windows search bar. Right-click the command prompt application and choose ‘run as administrator)
Type slmgr /ipk <ProductKey>
(Replace <ProductKey> with one of these below)
YTMG3-N6DKC-DKB77-7M9GH-8HVX7 – Use if you had Windows 10 Home. Even if you have upgraded to Pro through Windows Store
VK7JG-NPHTM-C97JM-9MPGT-3V66T – Use if you had Windows 10 Pro. Purchased as Pro and not upgraded from Home
BT79Q-G7N6G-PGBYW-4YWX6-6F4BT – Use only if you have a Single Language edition
Reboot the PC. (This step is important to complete the process)
