title: "Attachment Unavailable" on messages sent with FB.ui
body: <p>I'm trying to include a link and an image in messages I'm sending with the use of FB.ui({method: "send"});</p>
  
  <p>docs: <a href="https://developers.facebook.com/docs/reference/dialogs/send/" rel="nofollow noreferrer">https://developers.facebook.com/docs/reference/dialogs/send/</a></p>
  
  <p>Note that I've seen <a href="http://facebook.stackoverflow.com/questions/7385141/facebook-attachment-unavailable-error-when-using-the-send-button">this accepted answer</a> but it doesn't address my question.</p>
  
  <p>Sometimes the recipient can see the image and link and other times they see this:</p>
  
  <hr>
  
  <p><img src="https://i.stack.imgur.com/IeXNT.png" alt="enter image description here"></p>
  
  <hr>
  
  <p>Any idea what may cause this? The image is hosted on AWS CloudFront and is accessible via HTTP and HTTPS.</p>