Storyline 2 black play screen appearing over project on tablets and androids

Hi

We have used Storyline 2 for many projects and i am wondering if there is a way you can get rid of the black screen that appears over the session on such devices as Samsung Galaxy Tab, iPad and iPhones. Or even if anyone can recommend how we can make the black screen just be the size of the session. Once pressing the play button it works fine but feel it looks a bit messy. See attached screenshot.

We don't want to use the articulate app to view sessions.

Here is the embed code we have used: 

<div class="aspect-ratio"><iframe style="z-index: 99;" src="http://www.mtdtraining.com/sessions/Session3/story.html" width="100%" frameborder="0"></iframe></div>

We also tried this but found then our resources area on IE did not work correctly: 

<div class="aspect-ratio"><iframe style="z-index: 99;" src="http://www.mtdtraining.com/sessions/Session3/story_html5.html" width="100%" frameborder="0"></iframe></div>

We export the file for web.

Thank you for your help in advance.

Many thanks

Jenny