Certain pages keep displaying ‘load’ icon

Hi,

on some pages like http://www.galeriepaterswolde.nl/franzis-paula-maas/, the plugin doesn’t seem to load, neither in the gallery view on the page, or in the sidebar. The plugin works fine on other pages. Also, the linked image shows up on another page fine.

I tried deleting both the plugin-section and this whole specific page/ post and adding it again, but that didn’t work.

I’m not sure where I should look for a solution to fix this issue, since it affects all the plugin-elements on this specific post. I think this was the case since I created it, but I’m not sure.

Can you please offer me some insight?

The page I need help with: [log in to see the link]