title: Apple Transporter failing to upload IPA with error: Failed to create .itmsp for 'appname' status code 401
body: <p>I am trying to upload an ipa to Transporter (to get new version on TestFlight) and have successfully done it in the past. However, today I tried to upload and it stopped with this error popup on the screen:</p>
  
  <p>Failed to create the .itmsp for 'Appname'.
  The web service returned an unexpected status code (401 instead of 200) </p>
  
  <p>screenshot: <a href="https://i.stack.imgur.com/rKML2.png" rel="noreferrer">screenshot of error</a></p>
  
  <p>Notes:</p>
  
  <ul>
  <li>tried multiple times today with same issue</li>
  <li>App is a Xamarin app thus can't upload the other way (Xcode > Archive)</li>
  <li>using Transporter app released by Apple</li>
  </ul>