xtf on "[Plugin: Contact Form 7] Arrows turning endlessly"

I have a problem with contact form 7 as it is impossible to send messages. The form appears, you can fill it but once you push the send button, the arrows appear and turn endlessly and no message is sent.

I have already deactivated all plugins and change the Theme but nothing has changed.

Here is a link to my page where the form in integrated

http://www.nohellef.com/contact/

http://wordpress.org/plugins/contact-form-7/