3D FlipBook - 3D FlipBook items don´t show up anymore

Hello!

On https://www.swarovski-betriebsrat.at/ and https://www.swarovski-betriebsrat.at/kristall-klar/ 3D FlipBook items don´t show up anymore since a few weeks.

I checked some things and tried a few things (eg. deactivated our theme but also all of the other plugins). I have no clue, what the reason for this problem could be.

Thanks for your kind help, Best regards Markus