Lightbox not Working

Hi!

I’m quite new in regards to web design, so maybe it’s just a beginner’s mistake. But I spent a full day trying to figure out what’s wrong.

I built a small promotional website http://www.gaerten-und-parke.de and included a small gallery. All worked fine until tuesday, when we decided to go live and I changed the URL in the backend. Then suddenly all lightboxes stopped working.

I’m not sure if it was caused by changing the URL or if any other plugin caused a conflict. What I do know is that both affected plugins rely on jQuery. But neiter manually restoring the original jQuery from the WordPress-Installer, nor deleting all plugins I don’t really need or deleting and re-installing the affected plugins helped.

Any ideas?

P.S.: I’ll crosspost this in the forum of the second affected plugin. Hope it’s okay.

https://wordpress.org/plugins/photo-gallery/