How to fix error 0x803FA067Disconnect from the internet
Temporarily disable Wi-Fi or unplug the Ethernet cable.
Manually enter your product key
Go to:
Settings > System > Activation > Change product key
Enter the key you received and continue.
Reconnect to the internet
After the key is accepted, turn your connection back on and restart the PC.
Other helpful checks
Activated on another PC?
If your key is transferable, you may need to remove it from the previous device before using it on a new one. Make sure itβs only in use on one device at a time.
Reactivating after a hardware change?
You can try reactivation through your Microsoft account:
Settings > Activation > Troubleshoot > I changed hardware on this device recently