Not Working on custom Pages

Hello community,

could someone tell me why my simple Lightbox is working perfectly on a post page but not on my custom category page?

Is there something i should add to my custom code?

Here is one post example which is working: https://www.geigerundsoehne.com/zeit-fuer-eine-eindrucksvolle-weinreise/

Here is a custom page wich is not working: https://www.geigerundsoehne.com/secco-copy/

Thanks a lot in advanced!