[Plugin: Contact Form 7] Falls of the sending mensaje senders

Hello

http://www.lesmills.es/contacto/

have a problem, not because now does not allow sending mail from the web, gives a shipping error, I uninstalled and re-install, I upgraded to the latest version, but not because it fails, I looked at the log of the server and constacia no fault. You can help.

thanks

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