Couldn't set it up

I tried installing this plugin twice, trying to get it to work, but I ran into the same problem both times. In attempting to set up the plugin, I got an error message (orange outline, inside the text box for the pop-up text) about the default settings and that it would load the page. The page would refresh with the same error message, and try to reload again. This happened continuously until I finally closed the browser. I tried logging out of WordPress and logging back in again; I got the same result. As I mentioned above, I tried deleting and re-installing the plugin, but I got the same result.