How can we retrieve the calendar of an external user using the Microsoft Graph API?

Question

As an invited guest user in my tenant, I can successfully log in using the tenant application. However, external guest users are unable to make successful calls to the Azure API for retrieving the calendar list, whereas standard member users can call it successfully.

I am getting following errors:

{
  "error": {
    "code": "AuthOMMissingRequiredPermissions",
    "message": "The AadGuestPft token doesn't contain the permissions required by the target API for calling app '00000003-0000-0000-c000-000000000000'.",
    "innerError": {
      "oAuthEventOperationId": "bbfaa161-3680-4790-a0fc-f2d36f87ac6d",
      "oAuthEventcV": "P2yQe5CjjZSldssPbDc6vQ.1",
      "errorUrl": "https://aka.ms/autherrors#error-InvalidGrant",
      "requestId": "fdfb03dc-fb78-e966-15c7-63bb0390c94d",
      "date": "2024-01-19T12:40:26"
    }
  }
}

Answer 1

Hi Satish, I think there is a similar issue from previous post. Kindly refer to below link: https://learn.microsoft.com/en-us/answers/questions/1160460/microsoft-graph-api-how-to-access-guest-user-calen Hope this helps. If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".