Most recent computers with Windows 10 pre-installed will have a digital license. This is tied to the physical hardware of the device as well as the Microsoft Account used to sign in, so the key is not provided to you directly.
You can run the following command using Command Prompt and view your key:
wmic path softwarelicensingservice get OA3xOriginalProductKey
This might have been a bug that came through in an update. Try using the Activation Troubleshooter:
Here are some more detailed steps for specific activation errors:
If this does not resolve the issue, you should reach out to Microsoft directly. They can walk you through resolving this type of issue:
1-(800) 642 7676