Unknown error while using Microsoft Graph Communication API

Question

We are trying to use the Microsoft Graph Communication APIs in order to make the peer-to-peer calls based on the Create Call using Communication API

Based on the request payload when we try to fire the same query using Graph Explorer and the node.js sample we do get the same error

{
    "error": {
        "code": "UnknownError",
        "message": "",
        "innerError": {
            "request-id": "9342e7a0-2d26-4e59-b7f4-c89a4a52e2d5",
            "date": "2020-06-11T06:47:03"
        }
    }
}

So far we have created the App under the App Registration over Microsoft Azure and assigned the required permissions for Graph Api Calling

Request payload for create call that we are using is based on the Create Call Sample Request provided by Microsoft itself.

{
    "@odata.type": "#microsoft.graph.call",
    "callbackUri": "http://localhost:31544/",
    "targets": [{
      "@odata.type": "#microsoft.graph.invitationParticipantInfo",
      "countryCode": "91",
      "identity": {
        "@odata.type": "#microsoft.graph.identitySet",
        "user": {
          "@odata.type": "#microsoft.graph.identity",
          "displayName": "Maggie",
          "tenantId": "150d7f46-ce04-4895-b4bd-1112221122",
          "id": "a27c62fb-a420-4fa5-87eb-2221112121"
        }
      }
    }],
    "requestedModalities": ["audio"],
    "mediaConfig": {
      "@odata.type": "#microsoft.graph.serviceHostedMediaConfig"
    }
  }

Not sure what is wrong with the payload or URL as we do get 404 unknown error every time we execute the request.

Edit

1. I have granted all the required permissions now

2. Then I tried to call calling following URL for admin consent

   https://login.microsoftonline.com/common/adminconsent

3. after that I tried to call following URL in POSTMAN to get the token

   https://login.microsoftonline.com/{{TenantID}}/oauth2/v2.0/token

4. use the same token to make a call but getting the same error

   https://graph.microsoft.com/beta/me/communications/calls

Edit

5. Now after calling the following URL I do get error in POSTMAN

   https://graph.microsoft.com/beta/communications/calls

Error

{
  "error": {
    "code": "UnknownError",
    "message": "{\"errorCode\":\"7503\",\"message\":\"Application is not registered in our store.\",\"instanceAnnotations\":[]}",
    "innerError": {
      "date": "2020-06-12T16:11:47",
      "request-id": "d25c41fd-afc4-462b-a811-46e7286a0df6"
    }
  }
}

Answer 1

From the doc, the Delegated permission is not supported, it just supports Application permission, so you need to use the client credential flow to get the token and call the API(e.g. use the postman) instead of using the Microsoft Graph Explorer, in the Microsoft Graph Explorer, the Application permission will not take effect.

Also, I notice you don't click the Grant admin consent for xxx button in the API permission page of your AD App, it is required when you grant the permission for your app, the status should be like below.