Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Exit all Office apps and run an Online Repair. See https://support.microsoft.com/en-us/office/lifecycle/repair-an-office-application .
Since an Online Repair usually requires that you reinstall Office, before you begin, you should verify that you can access your account at https://account.microsoft.com/services and that Office is associated with it.