title: Can't create an event with extended data
body: <p>I am trying to create a calendar event with extended data using Microsoft Graph API.(actually, I am trying to converting the existing open extension to schema extension since I couldn't filter the non-id extended value of the open extension.)</p>
  <p>Before my try, I have already created <a href="https://stackoverflow.com/questions/65603715/cant-create-a-schema-extension">my schema extension</a> successfully and creating a calendar event with the schema extension responses an error code &quot;BadRequest&quot; and message &quot;Requests must contain extension changes exclusively&quot;.</p>
  <p>I tried to do this by following the <a href="https://docs.microsoft.com/en-us/graph/extensibility-schema-groups#3-create-a-new-group-with-extended-data" rel="nofollow noreferrer">doc</a>.</p>
  <pre><code>POST https://graph.microsoft.com/v1.0/me/calendars/{calendar-group-id}/events
  
  {
    &quot;subject&quot;: &quot;schema extension test&quot;,
    &quot;body&quot;: {
      &quot;contentType&quot;: &quot;HTML&quot;,
      &quot;content&quot;: &quot;schema extension test&quot;
    },
    &quot;start&quot;: {
        &quot;dateTime&quot;: &quot;2021-01-22T12:00:00&quot;,
        &quot;timeZone&quot;: &quot;Eastern Standard Time&quot;
    },
    &quot;end&quot;: {
        &quot;dateTime&quot;: &quot;2021-01-23T14:00:00&quot;,
        &quot;timeZone&quot;: &quot;Eastern Standard Time&quot;
    },
    &quot;attendees&quot;: [],
    &quot;extendedData&quot;: {
        &quot;courseId&quot;: &quot;11&quot;,
        &quot;materialId&quot;: &quot;22&quot;,
        &quot;courseType&quot;: &quot;video&quot;
    }
  }
  
  response: 
  {
      &quot;error&quot;: {
          &quot;code&quot;: &quot;BadRequest&quot;,
          &quot;message&quot;: &quot;Requests must contain extension changes exclusively.&quot;,
          &quot;innerError&quot;: {
              ...
          }
      }
  }
  </code></pre>
  <p>Without <code>extendedData</code>, creating the event responses success, and after creating the event, if I <code>patch</code> the event with only <code>extendedData</code>, it responses an error &quot;A type named 'Microsoft.OutlookServices.OpenTypeExtension' could not be resolved by the model. When a model is available, each type name must resolve to a valid type&quot;.</p>
  <pre><code>PATCH https://graph.microsoft.com/v1.0/me/calendars/{calendar-group-id}/events/{event-id}
      
      {
        &quot;extendedData&quot;: {
            &quot;courseId&quot;: &quot;11&quot;,
            &quot;materialId&quot;: &quot;22&quot;,
            &quot;courseType&quot;: &quot;video&quot;
        }
      }
  
  response:
  {
      &quot;error&quot;: {
          &quot;code&quot;: &quot;RequestBodyRead&quot;,
          &quot;message&quot;: &quot;A type named 'Microsoft.OutlookServices.OpenTypeExtension' could not be resolved by the model. When a model is available, each type name must resolve to a valid type.&quot;,
          &quot;innerError&quot;: {
              ...
          }
      }
  }
  </code></pre>
  <p>I was able to succeed when I used Graph API explorer with signed in user by consent <code>Calendars.Read</code> permission.</p>
  <p>But if I try the same thing in postman, it doesn't work.</p>
  <p>I already have granted all calendar permissions including delegated and application permissions in Azure.
  <a href="https://i.stack.imgur.com/NY5rs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NY5rs.png" alt="enter image description here" /></a></p>