I am trying to retrieve the outlook messages of an user using the following API end point -
https://graph.microsoft.com/v1.0/users/{userPrincipalName}/messages
However, it is not working at all. I am the admin and hence using my own credentials (instead of using an app)
It works fine if I want to see my own data with this call - https://graph.microsoft.com/v1.0/users/me/messages