Pop Up Doesn't display popup-no error message-just nothing

I installed and activated it, but the Pop Up I created doesn't work. I go to my site and nothing happens. I had only one rule, the one that says "Popover Shown Less Than." It's never shown, so that can't be the problem. Do you have any idea what I am doing wrong? I am using WP 3.8.1 with a custom theme based on Twenty Ten. Thanks.