When I test the form you have I can see that it does not go to the thank you page. Also, I noticed that there is no URL parameter appearing in the URL when you submit the form.
When you use the page by itself without putting the form into another page what result do you get? I think that there may be an issue with the way the form is currently setup on this page that is preventing it from submitting properly. If the form cannot be properly submitted it will not send back an email.