HTML video tag in asp.net not streaming

I need to display video in the page I used the html video tag and it works fine but when skip ahead the playing of the video the play stops and the video box became black .On the other hand I did it in normal HTML page outside asp.net it works fine but in the HTML page in asp.net not working 

 

 this the code 

autoplay="autoplay" onprogress="true" preload="metadata" onended="playnext()">

type="video/mp4">

Please help