The troubleshooting section on this post has some guidance: Tumult Hype Animations Wordpress Plugin
Using a percentage-based height in a responsive document may cause issues. If possible, only set scaling on the width dimension for your document.
If you uncheck the 'height' scaling checkbox, does this work?
Another note regarding what @JimScott shared: When you embed your OAM widget normally in the Wordpress plugin, there is no CSS included. So any CSS that Jim included would need to be added to your Wordpress site's style.css file. Or, you could insert it (the css Jim included below) within the innerHTML of a rectangle, but that's not the recommended method.