The redirect URI in the request, http://giampablo.altervista.org/forum/memberlist.php?mode=login&login=external&oauth_service=google, does not match the ones authorized for the OAuth client. To update the authorized redirect URIs, visit: https://console.developers.google.com/apis/credentials/oauthclient/406071359068-jnvcdrp1gm7i83h4dsss9bqanbbbl4t9.apps.googleusercontent.com?project=406071359068