Problems with image not responsive in mobile with Popup Pro

It's a simple popup with, only 1 image and 1 button. Can you help me, giving instructions to solve this issue?

The domain is:

I have another site:, with the same image and the free version of the same plugin, same version of Wordpress, same theme and everything its running fine.

I've bougth the pro version and installed it on the site that was the problem but don't see any changes.

Best regards,