Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
The best first option is to remove the Office licence using the steps provided on this link, then log back into the Office apps to test if that resolves the problem.
If that does not resolve the problem, at the top left of your Mac desktop, click the Apple icon and select 'About this Mac', what version of MacOS is installed on your computer?