title: iOS Push notification with video is not showing on lock screen
body: <p>I am testing notification service extension on iphone 7 (iOS 13.4). I am sending multiples media types (jpg, gif and mp4). The content with jpg and gif are showing good, but mp4 notification only shows content when iphone is unlocked. When iphone is locked and notification video played the image is not showing, white screen all the time, although the video is heard. if I press the touch button while video is playing with white screen the image appears.</p>
  
  <p>In the notification settings for the app all permissions are granted (I think).</p>
  
  <p>Do I have to ask the user for any special permissions? Any idea? </p>
  
  <p>Thanks.</p>