videos not playing after WordPress 3.9

Videos in my Videogall gallery are not playing since I updated to WordPress 3.9. Clicking on a thumbnail causes the white light box comes up, but the video does not play. The videos still play from the Vimeo links, I’ve tried deactivating & reactivating the plug-in, resetting Videogall settings, creating a new category, etc.

Gallery is at: https://www.skylightscope.com/instructions/

Any insight super appreciated!

https://www.ads-software.com/plugins/videogall/