Problem in Filter

Ihave code in Filter like this

PHP Code:

<?php

namespace App\Filters\API;

use CodeIgniter\Filters\FilterInterface;
use CodeIgniter\HTTP\RequestInterface;
use CodeIgniter\HTTP\ResponseInterface;
use Config\Services;

class GuestRequest implements FilterInterface
{
    public function before(RequestInterface $request)
    {

         //$req  = ( $request->getMethod()=='post' && $request->isAJAX() == TRUE$
        $req = $request->getMethod();
        $ajx = $request->isAJAX();

        if( $ajx == true )
        {
                Config('App')->data = (object)[$req, $ajx];
                Config('App')->time = microtime(true);
                return true;

        }


        return Services::response()
            ->setStatusCode(401);

    } 


In local (OS : linix mint, php 7.2) run normal
in VPS (OS Centos, php 7.2)
always return 401, although my codes change to
if( $ajx == false)