Getting "ErrorItemNotFound" when trying to acquire delta token for users using Graph Explorer

Question

Hi Team,
I'm trying to run the delta query in the Graph Explorer v1.0 signed in with Azure admin and unable to get the delta token for the users.

if I try to run the delta query using the below link, it is working fine

https://graph.microsoft.com/v1.0/me/mailFolders/inbox/messages/delta  

with the above Get call I'm able to get the skipTokens and after some more calls I'm able to get the delta token without any issue.

But if I try to get the delta token for other users using the below link

https://graph.microsoft.com/v1.0/users/abc@efgh.com/mailFolders/inbox/messages/delta  

I'm unable to get the delta token and the response for this request is like

{  
    "error": {  
        "code": "ErrorItemNotFound",  
        "message": "The specified object was not found in the store., Default folder Inbox not found.",  
        "innerError": {  
            "date": "2022-08-17T08:56:22",  
            "request-id": "xxxxx-xxxx-xxxx-xxxx-xxxxxxxxx",  
            "client-request-id": "xxxxx-xxxx-xxxx-xxxx-xxxxxxxxx"  
        }  
    }  
}  

However the above response is coming for 8 out of 10 users for which I have tried.

Can I know the reason for this kind of behavior, let me know if I'm missing something.

Answer 1

Hi @Prashanth Ettaboina ,

As per my test in order to get another user's mailbox messages and if the other user hasn't delegated their mailbox access in Exchange Online (like an administrative assistant might do) - we need to use Application permissions rather than Delegated (which acts on behalf of the user). Here is the relevant documentation.

As you are using Graph Explorer which works in a delegated scope, So to get rid of this error another user has to share his mail folder with the user who wants to access mail messages, or, has to give delegated access to that user which can be done from admin center.

Follow this documentation to get access token without a user (Client Credentials Flow): https://learn.microsoft.com/en-us/graph/auth-v2-service

Hope this helps.

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