lightgallery doesnt work on mobile devices

Hi
First of all, this template is really good!!
I have only one issue, if I check the website on a mobile device, the pictures doesn't open.
It opens the link which is in the background.
Here is the link: https://feger-hecht.flottefeger.ch/fullscreen.html
It would be really really great if you can help me?

Thanks a lot!
Br Roland