1
Click your Start Button, then just type cmd and on the resulting list, right click Command Prompt and select 'Run as Administrator'.
Run this command in Command Prompt and press Enter.
slmgr.vbs /ato
When that command completes, close Command Prompt and restart your PC, that command should force your system to contact the activation servers to reactivate your licence.
2
If that process is not successful and the troubleshoot method is not working to reactivate Windows, check in the Settings app to ensure the correct version (Home or Pro) is installed that matches the Windows licence you purchased.
If it is, you will need to contact Microsoft Support directly, they will be able to see your Windows licence on your account and reactivate Windows for you, this is just a user to user forum, no-one here has any account access.