Admins may face an error message in the Microsoft 365 Connection Settings:
The message 'The refresh token has expired due to inactivity' is displayed in case the Course Catalog was inactive for a certain period of time and no email notifications were sent which are required for the token to keep refreshing itself.
The default lifetime for the tokens is 90 days and they replace themselves with a fresh token upon every use. So in case of inactivity no fresh tokens are obtained. To find more about refresh token functionality please follow Microsoft identity platform refresh tokens