Hi Isha. I'm Greg, 10 years awarded Windows MVP, here to help you.
There are some reasons for the error here:
https://support.microsoft.com/en-us/windows/win...
Where did you get the license? Was it a heavily discounted key as this usually means it's bogus, there are no deep discounts for Windows retail software.
If you're trying to change to Pro version and then activate when it fails, change to Pro using the Pro Generic Version Key VK7JG-NPHTM-C97JM-9MPGT-3V66T in Settings > Update & Security > Activation > Change Product Key. This will change the version to Pro.
Then try using the key again, or signing into the MS Account with which you bought the Digital License to follow the steps in the email you received.
If further problems, run the Activation Troubleshooter at Settings > Update & Security > Troubleshoot > Additional Troubleshooters. Report back everything it says.
Also tell me as much as you can about where you got the license, how you attempted to use it, whether it's been used before and where.
Based on the answers you post back I may have other suggestions.
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