Hello,
Do you have a legitimate product key?
Select Start > Settings > System > Activation, and then select Change product key to enter the key.
If that doesn't work, we recommend that you use phone activation.
- Select Start > Settings > System > Activation.
- Under Activate Windows Now section, select Activate by Phone.
Have you made significant hardware changes recently? For example, replacing the motherboard.
A Windows license is associated with your device hardware. If Windows is preinstalled on your device and you make a change, such as replacing your motherboard, you'll need a new license. You can buy it in the Microsoft Store.
More details please refer to this link:
Best Regards,
Hania Lian
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