Popup box working, but not showing whats actually on the page

I have a strange problem probably to do with the custom theme i had made for a site. Problem I’m experiencing is that the post that we add the popup box to, will not show. Only a empty page. If you do scroll to the bottom the popup activates and works as it should. Any suggestions?

Link to post: https://ideogram.no/kunder/ff.html

https://www.ads-software.com/plugins/scroll-triggered-boxes/