title: Read contact with data extension from shared mailbox
body: <p>I try to create and read a contact in a shared mailbox using the Microsoft Graph API. So far, I managed to create a contact with an extension like this: </p>
  
  <pre><code>POST https://graph.microsoft.com/beta/users/&lt;SMB-ID&gt;/contacts
  "extensions":[
      {
          "@odata.type": "#Microsoft.Graph.OpenTypeExtension",
          "extensionName": "specialdata",
          "key1": "yes"
      }]
  
  Response:
  {
    ...
    "extensions": [
    {
      "@odata.type": "#microsoft.graph.openTypeExtension",
      "id": "Microsoft.OutlookServices.OpenTypeExtension.specialdata",
      "key1": "yes"
    }
    ]
  }
  </code></pre>
  
  <p>My problem is that I can read the contact without extension but not with it via GET. Both ways described in the <a href="https://graph.microsoft.io/en-us/docs/api-reference/beta/api/opentypeextension_get" rel="nofollow noreferrer">docs</a> don't work.</p>
  
  <pre><code>GET https://graph.microsoft.com/beta/users/&lt;SMB-ID&gt;/contacts?$expand=extensions($filter=id eq 'specialdata')
  Response:
  {
   "error": {
   "code": "ErrorAccessDenied",
   "message": "Access is denied. Check credentials and try again.",
   "innerError": {
       "request-id": "441d4fd6-52a5-460a-a972-cddcd87222ee",
       "date": "2017-02-08T14:40:48"
       }
   }
  }
  </code></pre>
  
  <p>The scope of my Bearer Token looks like this:</p>
  
  <pre><code>"scp":
  "
  Calendars.Read.Shared
  Calendars.ReadWrite.Shared
  Contacts.Read.Shared
  Contacts.ReadWrite.Shared
  full_access_as_user
  Mail.Read.Shared
  Mail.ReadWrite.Shared
  Mail.Send.Shared
  User.Read"
  </code></pre>
  
  <p>Am I missing a permission in Graph, the shared mailbox or is it an unsupported feature?</p>