Visual Composer & Page Builders
Visual Composer and other page builder plugins have been known to cause problems with AppPresser.
As AppPresser switches the active theme inside the app, any page builder functionality bundled inside the theme code will not run and will likely cause any page depending on the page builder not to display correctly.
If your page builder if installed as a plugin then it should at least render your content within the AppPresser. There could still be styling issues present if your pages relied on CSS from the website theme which you need to resolve yourself by adding custom CSS to an AppPresser child theme.