stitched 360 video taken using Samsung Gear 360 dark in aframe <a-scene> <a-assets>

Question

I used the exact same code sample used on aframevr/aframe 360-video example.

All I changed was the source URL. But the only thing we see is a dark page, not the 360 video we shot with our Samsung Gear 360.

<a-scene>
   <a-assets>
     <video id="video" src="http://siteurl.net/vrvid/cattle.mp4"
           autoplay loop crossorigin="anonymous"></video>
   </a-assets>

   <a-videosphere src="#video" rotation="0 180 0"></a-videosphere>
</a-scene>