Jetpack Contact Form Rarely Works

I'm a complete newbie so I'm not sure if this post belongs here or somewhere else.

I use the Jetpack Contact form on my website. After filling out the form and sending, another page comes up with a rather non-specific message: "Are you sure you want to do this?" and offers no choices for response.

Any ideas on the cause or what else I can do to further diagnose the problem?

Thank you!

www.selmarcerini.com