plugin stopped workling on live site..

Hey there!

Suddenly the plugin stopped working on my live site..
I have an image on my local computer, whichz still works like a charm.

I updated the plugin for the live site, and my local test site…
still not working on the live one..

any idea what might have caused it ? (no other updates had been made for quite a while)…
only thing different is, that there is a new WP 4.0 out, which I didnt install on the live one…

https://wordpress.org/plugins/responsive-lightbox/