Rainloop installation, unable to see anything on the page

Hi. Trying to install Rainloop Webmail https://www.rainloop.net/
but when i fire up the page, i cannot see anything. Here is my system:
Code: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: ~ $Here are the steps that i follow:
-Code: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-Code: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-Code: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.serviceBut when i fire the http://IP_address all i see is a blank page in firefox, while in Chrome is see:
PHP Code:<?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);
}Any ideas please?