Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Since Repair Now does not work, exit all Office apps and run an Online Repair. See https://support.microsoft.com/en-us/office/lifecycle/repair-an-office-application .
Before you begin, verify that you can access your account at https://account.microsoft.com/services and that Office is associated with it. This lets you reinstall Office after the repair (required step in most cases).