Hello,
I think I have the same issue with the same theme (Elegant Themes Divi). When I set up a package to lock a download (password or email for example), the dialog box does not appear when I click on the download link, the page floats down as if the box has been drawn, but nothing is visible.
At the moment, I’m working with xampp (local) with windows 8, Firefox
Thanks for your help
EDIT : I’ve dounf a workaround by using a new template with [download_link_extended] but I liked the pop-up effect … so if you have any idea to fix this …