Glitch on IOS

At the bottom of my page I have few links in the footer where the text has hyperlink that leads to pdf file (it opens it as the flipbook in the fullscreen mode), when I close the flipbook I’m not able anymore to click anything on the page, neither open other pdf files. I found out it only doesn’t work on my iPhone but on my Samsung fold (tested phone mode and tablet mode) and PC works with no problem. I also used different browsers to see if that might be a problem, but no. I don’t have a Mac to test if it’s a problem for all IOS devices but for now its just iPhone thing. Could you fix the bug or maybe give me direction how to try to fix it if possible.

The page I need help with: [log in to see the link]