title: Outlook WebAddin throwing internal server error when registering Office.EventType.ItemChanged
body: <p>In my outlook WebAddin, i am trying to register for mail ItemChange event using below code.</p>
  
  <pre><code>    Office.context.mailbox.addHandlerAsync(Office.EventType.ItemChanged, mailItemSelectionChanged, [], function (result) {
              if(result &amp;&amp; result.status != 'succeeded'){
                  console.error('result =&gt; ' + result);
               }
  });
  </code></pre>
  
  <p>Whenever user changes mail in pinned mode, i receive mail change event for first time. then if there is change in conversation, i am reloading the plugin with <strong>location.reload()</strong> to clear the cache and load addin fresh.</p>
  
  <p>After reload of plugin, it fails to register mailItemChange event and throwing below error : </p>
  
  <blockquote>
    <p>{"code": 5001, "message": "An internal error has occurred.", "name":
    "Internal Error"}</p>
  </blockquote>
  
  <p>It is failing in Browser and some windows machines(working in many other cases). </p>
  
  <p><strong>outlookDiagnostics</strong> : </p>
  
  <blockquote>
    <p>{"host": "Outlook", "platform": "OfficeOnline", "version":
    "16.0.9215.1000"}</p>
  </blockquote>