Ciao,
I'm Ugo, a Microsoft Independent Advisor willing to help other Microsoft customers.
Regarding your question, please find an extensive Microsoft post on Windows/Office activation:
https://support.microsoft.com/en-us/help/326851...
Other useful information can be found below:
WINDOWS ACTIVATION TROUBLESHOOTER
https://support.microsoft.com/en-us/help/20527/...
REACTIVATING WINDOWS 10 (RETAIL) AFTER HARDWARE CHANGE
https://support.microsoft.com/en-us/help/20530/...
CANNOT ACTIVATE WINDOWS ON THIS DEVICE: TRY AGAIN LATER
https://www.kapilarya.com/we-cant-reactivate-wi...
TRANSFER WINDOWS 10 LICENSE TO A NEW COMPUTER
https://www.groovypost.com/howto/transfer-windo...
If non of the above worked, you can:
CONTACT SUPPORT
https://support.microsoft.com/en-us/contactus/
Please let me know if this helped somehow.
Ciao
Ugo