HTML iframe won't display content

I am using Inkscape to create slides detailing a tutorial. I uploaded the slides to Sozi so I could make them fade in/out and look nicer. I have done this before with a Sozi presentation and it worked perfectly. Here is the code from the working presentation:

<iframe src="lessonFlow3.sozi.html">
	Sozi presentation here
</iframe>

Here is the code from the presentation that is not working:

<iframe src="planLessonMovie.sozi.html"> 
	Planning movie here 
</iframe>

Here is the CSS I have to format the iframe tag:

iframe {
	border: 1px solid black;
	width: 100%;
	height: 550px;
}

And finally, here is a screenshot of what the problem presentation is displaying like on my web page.

Anything helps!! Thank you