I'm sorry about the issue. Have you tried to reset the Microsoft account password ***** the email address as shown on the problematic windows 10 computer at the website https://account.live.com/ResetPassword.aspx (using your working computer)?
If that does not work, is it okay to reset the problematic windows 10 fresh, so you can re-set it up fresh, with a new password ***** want?
Please reply at the box below to continue troubleshooting. Thank you.