Excel Worksheet loading error [401] You do not have permission

I am aware that this topic was addressed about a year ago, see attached. Now I am experiencing it, does anyone know if MS fixed it or does it occur again?
any advice on how to solve or a detour is welcome.

reconnect your excel . your connection is expired

Thanks, but I’ve tried that several times now. That’s not solving the issue.

Additionally, it happens only when the Excel sheet is closed, not when it is open.
We’ve checked and adjusted the scopes, does not work either.

I’ve found the solution in another post that I cannot find anymore (sorry)

I was logged in in my personal MS account, although I had no applications open. Logging off of that account solved the problem.