A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Sorry to hear that you are having trouble with this situation. Have you tried the following steps?
- Open the app and use the menu bar: App name menu > Sign Out.
Restart your Mac.
Open Excel again and sign in with the account you want to use.
If this does not resolve the issue, please try using the license removal tool mentioned in this article: https://support.microsoft.com/microsoft-365-activation-licensing/how-to-remove-office-license-files-on-a-mac