Howdy, Ruben. I believe that the problem is stemming from the response time of your first page. That is to say, it took me 14.3 seconds to load just your HTML in my browser (you can see this in Chrome using the built in developer tools). The online tool is likely timing out.
You can either analyze this with our browser extensions:
But I would really recommend working on speeding up that first page. 14 seconds is a long time! People will generally recommend getting your page under 1 second, or even .1 seconds.