Rainloop πρόβλημα εγκατάστασης

[atux_null]

Χαίρεται. Προσπαθώ να κάνω εγκατάσταση το Rainloop Webmail https://www.rainloop.net/ αλλά στον firefox browser δεν δείχνει τίποτα, ενώ στον Chrome

<?php

if (!defined('APP_VERSION'))
{
    define('APP_VERSION', '1.15.0');
    define('APP_VERSION_TYPE', 'community');
    define('APP_INDEX_ROOT_FILE', __FILE__);
    define('APP_INDEX_ROOT_PATH', str_replace('\\', '/', rtrim(dirname(__FILE__), '\\/').'/'));
}

if (file_exists(APP_INDEX_ROOT_PATH.'rainloop/v/'.APP_VERSION.'/include.php'))
{
    include APP_INDEX_ROOT_PATH.'rainloop/v/'.APP_VERSION.'/include.php';
}
else
{
    echo '[105] Missing version directory';
    exit(105);
}

Το σύστημα μου είναι

root@debian: ~ $ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 10 (buster)
Release:        10
Codename:       buster
root@debian: ~ $

και τα βήματα εγκατάστασης:

apt-get install apache2 unzip wget -y
systemctl stop apache2.service
systemctl start apache2.service
systemctl enable apache2.service
cd /var/www/www/html
rm index.html

apt-get install -y php7.3-fpm libapache2-mod-php7.3 php7.3-xml php7.3-curl php7.3 libapache2-mod-php7.3 php7.3-common php7.3-curl php7.3-mbstring php7.3-xmlrpc php7.3-mysql php7.3-gd php7.3-xml php7.3-json php7.3-cli

cd /tmp
wget http://www.rainloop.net/repository/webmail/rainloop-community-latest.zip
unzip rainloop-community-latest.zip -d /var/www/html
find /var/www/html -type d -exec chmod 755 {} \;
find /var/www/html -type f -exec chmod 644 {} \;
chown -R www-data:www-data /var/www/
systemctl reload apache2.service

Καμιά ιδέα, παρακαλώ?