Hello WPMUDEV team,
Normally the popup pro plugin is very reliable, but we have run into some issues. The popup was working fine about a week ago, but through updates or some other trickery the popup does not show anymore and instead puts a black opacity over the whole screen which you cannot click through. Obviously we cannot keep using this on our main page, so to help out support we made a page here:
that has a single button to display the popup. Some more info; we are using the same code for a similar popup on a different site that is still working.
Thanks for your help!