<?php

require_once 'class-IXR.php';
$rpc = new IXR_Client('http://localhost/wordpress/wordpress/xmlrpc.php');



$result = $rpc->query('pingback.extensions.getPingbacks','http://localhost/wordpress/wordpress/2018/01/17/hallo-welt/&post_type=something');

if(!$result) {
echo 'Error [' . $rpc->getErrorCode() . ']: ' . $rpc->getErrorMessage();

}

var_dump($rpc->getResponse());


?>

Error [0]: array(2) { ["faultCode"]=> int(0) ["faultString"]=> string(0) "" }