Wordpress - Jetpack plugin not working

I'm striving to get Jetpack plugin working into Wordpress (stevi.altervista.org/wp)

Error Details: The Jetpack server was unable to communicate with your site [HTTP 403]. Ask your web host if they allow connections from WordPress.com. If you need further assistance, contact Jetpack Support: Support ? Jetpack for WordPress

Please, note that I've already checked the presence of wordpress.com into the white list.

Do you know how to solve this problem?


Thanks a lot.

You have to enable XML-RPC in WordPress' settings.