Gallery Lightbox does not work

I have been using the Catch Evolution Pro theme for about a year, and suddenly after one of the latest updates of WordPress the lightbox portion of the photo gallery is no longer working. I have switched back to the standard Twenty Sixteen theme and it works fine. I have also turned off all of the installed plugins while using the Evolution Pro theme and it stops working. So this leads me to believe that the problem is with the theme. When I click on an image thumbnail, the image opens at full size in a new window, rather than in the lightbox. I am using Gallery by BestWebSoft as the gallery plugin. Can anyone help me fix this problem?