A family of Microsoft word processing software products for creating web, email, and print documents.
Hello, thank you for reaching out to Microsoft Q&A.
Could you please check if the banner disappears after signing in again with your Microsoft account?
To do this, go to File > Account > Sign out. (Sign out of all accounts)
Then sign in with the Microsoft account that is associated with your Microsoft 365 subscription.
If you are still having issues, open Credential Manager in the Control Panel.
Select Windows Credentials.
Remove the Microsoft Office credentials.
Finally, sign out and sign back in with your account in the Office apps.
Let me know how it goes.