title: Custom Sound not playing for Push Notifications
body: <p>Using Backendless for Push Notifications, and my devices successfully receive them. But when I try to set the "ios-sound" parameter of the message to an mp3 I added to my project, it does not play any sound:</p>
  
  <p><a href="https://i.stack.imgur.com/Isp1w.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Isp1w.png" alt="enter image description here"></a></p>
  
  <p>Here in <a href="https://backendless.com/documentation/messaging/ios/messaging_publish_push_notifications.htm" rel="nofollow noreferrer">the Backendless docs</a> it says that setting "ios-sound" does the following:</p>
  
  <blockquote>
    <p>Sets either a URL for the sound notification to play on the device or
    an array of bytes for the sound to play.</p>
  </blockquote>
  
  <p>I can't figure out what I'm doing wrong. Hmm...</p>