Getting Error Code: ErrorInvalidUser when trying to get message using GET /v1.0/users/{user-email}/messages/{message-id}

Question

I am using an Outlook Add-in which follows SSO as the authentication service and On Behalf Of Flow as the authentication grant flow . When retrieving the message using graph API I am getting following error for some Azure AD users.

Code: ErrorInvalidUser  
Message: The requested user 'abc@testdomain.com' is invalid.  

I am using following API call to get message.

https://graph.microsoft.com:443/v1.0/users/{user-email}/messages/{message-id}?$select=subject%2C%20body%2C%20internetmessageheaders%2C%20parentFolderId

They are using Microsoft O365 MSO (Cloud) offering a Microsoft Office E3 license.

Answer 1

Hi @Piyumi Perera ,

The above error code tells that the above user is invalid or doesn't exist. Check whether the user exists in portal.office.com

If the user exists, using this endpoint GET https://graph.microsoft.com/v1.0/users, you can query all the users in your tenant. In the response, The response contains id and userPrincipalName that can be used to request the /messages endpoint. Have you tried using other users on this issue?

You can refer to this documentation to get a token.

Hope this helps.
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