On registration page, i get redirected to default WP signup page..

Hello, when I enter my username and password to register, i get redirected to the default WP signup page (http://www.loccasionesardegna.it/new/wp-login.php?action=register).

You can check here, Classifieds SignIn page: http://www.loccasionesardegna.it/new/classifieds/signin/

Thank you,
Luca