Fatal error: Uncaught Error: Class "IXR_Client" not found in D:\XAMPP\htdocs\UTeM\penerbit\wp-includes\IXR\class-IXR-clientmulticall.php:8 Stack trace: #0 {main} thrown in D:\XAMPP\htdocs\UTeM\penerbit\wp-includes\IXR\class-IXR-clientmulticall.php on line 8