When trying to access the Graph Service Client using I am receiving the error :
Code: Authorization_RequestDenied
Message: Insufficient privile
In some cases the actual issue happens because we use "Application permissions" instead of "Delegated permissions". In my application, I have tried to list all the users with application permissions and it wasn't working. When I switched to a delegated permissions, it worked.
So, some quick check would be like this:
Hopefully, this would help someone.