Warning: main(/var/www/html/wp-includes/class-IXR.php): failed to open stream: No such file or directory in /var/www/html/xmlrpc.php on line 36

Warning: main(): Failed opening '/var/www/html/wp-includes/class-IXR.php' for inclusion (include_path='.:/php/includes:/usr/share/php') in /var/www/html/xmlrpc.php on line 36

Fatal error: Class wp_xmlrpc_server: Cannot inherit from undefined class ixr_server in /var/www/html/xmlrpc.php on line 66