Jwplayer Vast ad is not workign in Android and Ios Devises. But its working in Desktop

Hi am developing Html5 based mobile app for Android and Ios. I need to implement JWplayer in my app. Have implemented it successfully and the video is working fine. The problem is vast tags are not working in android and ios. But Vast tags and videos are working fine in my desktop.

In order to make it work what shall I do.