Clicking an image only opens a black overlay

I’m developing a site at https://www.sandbarmedia.com/clients/va/bathroom/ and am trying to use the Fullscreen Galleria plugin, but clicking on an image just opens up a black overlay with navication buttons. Clicking on the buttons doesn’t seem to do anything, and the only way to get out of the page is go back in your browser. Any ideas?

https://www.ads-software.com/extend/plugins/fullscreen-galleria/