title: App Preview submission, video has audio that is not two-channel
body: <p>When submitting my App Preview, iTunes Connect says: 
  "This video has audio that is not two-channel, no-surround stereo. Please refer to Apple's documentation for appropriate formats."</p>
  
  <p>Well heres the catch, when I created my App Preview in iMovie, I deleted the audio track! </p>
  
  <p>After giving up for a while, I came back and tried again, then I was receiving an error saying "file could not be loaded". </p>
  
  <p>Each time I go to submit for review, my App Preview disappears.</p>
  
  <p>Any ideas on how I can get my App Preview successfully submitted?</p>