Viewing PDF in Your Demo at https://www.joomunited.com/joomla-demo/dropfiles/default-theme-demo doesn't work in the pop up window. It just shows html code - See enclosed file
Does Viewing PDF not work? Can you show me an example of it working properly?
I've tried your PDF preview, DOCX preview in different browsers (Chrome, Firefox, Edge) and the only preview that works without sowing a bunch of HTML code is the JPG preview.
Is it a bug on your side or is it just not possible with your extension?