Microsoft Graph: Get delta on shared mail folder

Question

If I ([email protected] = logged in user) try to get a delta on a mail folder another user ([email protected]) shares with me...

https://graph.microsoft.com/v1.0/users/[email protected]/mailFolders/OtherUsersInboxFolderId==/messages/microsoft.graph.delta?$filter=ReceivedDateTime%20ge%202021-04-01T08:00:00.0000000Z

... I get an ErrorItemNotFound:

{
    "error": {
        "code": "ErrorItemNotFound",
        "message": "The specified object was not found in the store.",
        "innerError": {
            "date": "2021-04-19T10:00:00",
            "request-id": "<GUID>",
            "client-request-id": "<GUID>"
        }
    }
}

If I do not request a delta but simply the messages in that folder, the request succeeds and returns the expected messages:

https://graph.microsoft.com/v1.0/users/[email protected]/mailFolders/OtherUsersInboxFolderId==/messages

If I ([email protected]) try to get a delta for the Inbox folder of a shared mailbox ([email protected]), the request also succeeds:

https://graph.microsoft.com/v1.0/users/[email protected]/mailFolders/SharedUsersInboxFolderId==/messages

https://docs.microsoft.com/en-us/microsoft-365/admin/email/create-a-shared-mailbox?view=o365-worldwide

So now my question is: Why do deltas not work on folders another user shares with me? Is it simply not implemented in the Graph API or am I doing something wrong?

Answer 1

Delta call is not supported on a shared mail folder and that is why you get 404.