Why is Opencart 1.5.6 not working on my hosting?

Question

Apache HTTP Server

Hello. I have my own server on ubuntu 16.04.
Worth Apache.
Server version: Apache/2.4.18 (Ubuntu)
Server built: 2017-09-18T15:09:02
Installed php 5.6 to run OpenCart 1.5.6 (old version).
PHP 5.6.31-6+ubuntu16.04.1+deb.sury.org+1 (cli)
This page is here: tm.webboxua.com
On a laptop with OpenServer everything works fine.
I uploaded it to the hosting, everything works too (there is also something in the role of a unix system)
What is wrong with my hosting ??? Where to dig?
Here is the config file:

<?php
// HTTP
define('HTTP_SERVER', 'http://tm.webboxua.com/');

// HTTPS
define('HTTPS_SERVER', 'http://tm.webboxua.com/');

// DIR
define('DIR_APPLICATION', '/var/www/tm/catalog/');
define('DIR_SYSTEM', '/var/www/tm/system/');
define('DIR_DATABASE', '/var/www/tm/system/database/');
define('DIR_LANGUAGE', '/var/www/tm/catalog/language/');
define('DIR_TEMPLATE', '/var/www/tm/catalog/view/theme/');
define('DIR_CONFIG', '/var/www/tm/system/config/');
define('DIR_IMAGE', '/var/www/tm/image/');
define('DIR_CACHE', '/var/www/tm/system/cache/');
define('DIR_DOWNLOAD', '/var/www/tm/download/');
define('DIR_LOGS', '/var/www/tm/system/logs/');

// DB
define('DB_DRIVER', 'mysqli');
define('DB_HOSTNAME', 'localhost');
define('DB_USERNAME', 'ххххххххххх');
define('DB_PASSWORD', 'ххххххххххх');
define('DB_DATABASE', 'yyyyyyyy');
define('DB_PREFIX', 'oc_');
?>

Thanks in advance for your replies.