Jetpack Comments Shortcode Shows, not the form

Hi everyone,
I am trying to use Jetpack Comments on my website; katskinner.com/contact/.
I created a new page, and then used the form builder to create the form, which then added the shortcode to my page. However whenever I view the page – either logged in as admin or not – only the shortcode is shown (the form is never generated).

I am creating my theme myself. I just need to know why this is happening and how to fix it please.

Thanks in advance,
Kat