PopUp Pro slowly stops working - I'm stumped!

Hi Guys,

PopUp pro has been great so far, but the last few days, popups have started to not work here and there. If one of them stops working, I will re-save it in the PopUp Pro settings and it will start working again, however this will cause another popup to stop working. It always seems like there are at least 1 or 2 not working.

Here is my setup:
- Latest version of Wordpress
- Latest version of PopUp Pro (I even tried reverting back to the last version, but that didn't seem to help)
- Managed hosting by Flywheel: https://getflywheel.com/ - I know they use some kind of caching, but that hasn't effected PopUp Pro before
- I'm beginning to think it is some kind of conflict with our SSL, because it works in a staging environment where SSL is turned off

I'm really stuck here! I want to keep using this plugin because it has been great and is perfect for what we need. Please help!