I'm wondering if we just found a bug in the MS Graph API. I'm trying to access a different user's inbox mail rules via MS Graph. Here's what I did:
1.) Registered an application on the V1 Azure AD Endpoint, with ALL delegated permissions (including MailBoxSettings.Read and MailBoxSettings.ReadWrite) 2.) Granted access to the application using a global admin account 3.) Got a Graph Bearer Token for the tenant & proper permissions: 4.) Delegated mailbox access (full access) to my Global Admin account in Exchange Online settings: 5.) Verified that I have access to the users inbox via Graph: 6.) Attempting to list messagerules for this user fails:
Note that retrieving the current (global admin) user's mail rules works without an issue: GET /https://graph.microsoft.com/v1.0/me/mailfolders/inbox/messageRules
This tells me that there is probably a bug in MS Graph - or am I maybe missing something?
Thanks in advance
Ben