Почему не работает авторизация на Facebook?

class AuthViaFacebook {

    function get_user( $social_config ) {
		global $config, $lang;

		$params = array(
			'client_id'     => $social_config['fcid'],
			'client_secret' => $social_config['fcsecret'],
			'code' => $_GET['code'],
			'redirect_uri'  => $config['http_home_url'] . "index.php?do=auth-social&provider=fc"
		);

		@parse_str(http_get_contents('https://graph.facebook.com/oauth/access_token' . '?' . http_build_query($params)), $token);

		if (isset($token['access_token'])) {

			$params = array('access_token' => $token['access_token'], 'fields' => "id,name,email,first_name,last_name");

			$user = @json_decode(http_get_contents('https://graph.facebook.com/me' . '?' . http_build_query($params)), true);

			if (isset($user['id'])) {

				return array ('sid' => sha1 ('facebook'.$user['id']), 'nickname' => $user['name'], 'name' => $user['first_name'].' '.$user['last_name'], 'email' => $user['email'], 'avatar' => '', 'provider' => 'Facebook' );

			} else return $lang['social_err_3'];

		} else return $lang['social_err_1'];

    }

}