Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hello, thank you for reaching out to Microsoft Q&A.
Could you please confirm whether it is asking you to upgrade to Microsoft 365?
If so, you can run the Office License Removal Tool to remove any previous Office licenses on your Mac, and then reactivate your new license. You can download and run this tool from the official Microsoft website.
For detailed steps, see: