Popup with Popup PRO don't appears

I just bought back this plugin to take advantage of the support, so I hope that you will solve my problem.

In June I bought for the first time this plugin and I always used without problems on any of my sites. A few days ago I decided to use this template also on another web site, using the same settings, but unfortunately the popups don't appears.

For testing, now I set the activation popup every 2 seconds.

Information that could help to understand the source of the problem:

- site: browser-game.it
- If I browse the site logged in, the popup appears. If I browse the site as normal visitor, or anonymous surfing, the popup don't appears.
- I tried to set a non-AJAX opening (footer) and in this way it works. Unfortunately, however, I use caching and I need to run the method Wordpress Ajax (just like the other website where I have the same caching and use the pop-up without problems).
- The two sites have the same templates and the same plugins, making the situation even more strange.

Can you help me?
Support Staff Access already active.

Thank you.