使用PHP 5.6加载页面时出现502 Bad Gateway，但使用PHP 7.3加载时，此行返回502 Bad Gateway echo $ application-> handle（）-> getcontent（） >

PHP版本：5.6.33-0 + deb8u1

已加载的Phalcon：3.4.0

NGINX配置

location / {
        index index.php index.html index.htm;
        try_files $uri $uri/ /index.php?_url=$uri&$args;
        disable_symlinks off;
   }

   location ~ [^/]\.php(/|$) {
       # With php5-fpm:
       fastcgi_pass 127.0.0.1:9000;
       fastcgi_index /index.php;
       fastcgi_hide_header X-Powered-By;
       include fastcgi_params;
       fastcgi_param PATH_INFO $fastcgi_path_info;
       fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
       fastcgi_read_timeout 600;
   }

index.php

<?php

try {

    //Register an autoloader
    $loader = new \Phalcon\Loader();

    $loader->registerDirs(array(
        APPLICATION_CONTROLLERS,APPLICATION_MODELS,APPLICATION_CORE,APPLICATION_PHALCON_INCUBATOR,APPLICATION_LISTENERS,APPLICATION_TRAITS
    ))->register();

    $loader->registerNamespaces(array(
        'Erp\Backend\Models' => APPLICATION_MODELS,'Erp\Backend\Core' => APPLICATION_CORE,'Erp\Backend\Validators' => APPLICATION_VALIDATORS,'Phalcon' => APPLICATION_PHALCON_INCUBATOR,'Erp\Backend\Listeners' => APPLICATION_LISTENERS,'Erp\Backend\Traits' => APPLICATION_TRAITS
    ),true);


    //Create a DI
    $di = new Phalcon\DI\FactoryDefault();

    $di->set('dispatcher',function () use ($di) {
        $dispatcher = new Phalcon\Mvc\Dispatcher();
        return $dispatcher;
    });


    //Setup the view component
    $di->set('view',function () {
        $view = new \Phalcon\Mvc\View();
        $view->setViewsDir('../application/views/');

        return $view;
    });

    //Handle the request
    $application = new \Phalcon\Mvc\Application($di);
    echo $application->handle()->getcontent();

} catch (\Phalcon\Exception $e) {
    echo 'PhalconException: ',$e->getMessage();
}

无法找出问题所在。有人可以帮我吗？