You might see this error if you entered an invalid product key or a product key for a different version of Windows. Enter a valid product key that matches the version and edition of Windows 10 installed on your device. You may try these steps below:
1. Click on the Troubleshoot tool at the bottom of the error message.
2. Restart and/or update your computer, then enter the 25-digit activation key.
1. Order / Transaction ID
2. PayPal email address and/or Delivery email address (if different from PayPal email address)
3. Type manually the product key (code or pre-loaded account details)
4. Screenshot of the pop-up/error message
5. Additional information (if any)