Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
- Close all your Office Applications.
- Delete the 'HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity' hive.
- Re-launch the Office App and wait for a few seconds (re-login to Office Apps in case you get a prompt) to re-create the hive we deleted above.
- Close and re-launch your Office Apps and this should address your issue.