Server Requirements

Published websites

Reference:

Requirements for published websites Cloud On-Premises

Apache 2.2 (or newer) / LiteSpeed / Nginx / Microsoft IIS
Required Apache modules: rewrite, headers
PHP 5.6 (or newer)
Required extensions: json, curl, mbstring, iconv, openssl
Required functions: ini_set
MySQL not needed
ionCube Loader not needed
Hardware: any
Operating system (OS): any

Nginx if used instead of Apache

Configuration for published websites: Cloud On-Premises

If you want to use NGINX Web Server instead of Apache for published websites you need to configure separate virtual host (server configuration) for every website you will publish to. Ex. if web-sites you want to publish to domain is some.site.domain and it's document root is at /home/site/public_html you could set server configuration to something like this:

listen       80;
server_name  some.site.domain;

charset utf-8;
root /home/site/public_html;

index  index.php;

location ~ /(\.ht|error_log|php_errors\.log)|^/sitepro/(vendor/|src/) {
	deny  all;
}

location ~ \.php$ {
	fastcgi_pass   127.0.0.1:9000;
	fastcgi_index  index.php;
	fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
	include        fastcgi_params;
}

location / {
	try_files /sitepro$uri /sitepro$uri/ /sitepro/index.php?$args;
}

Show configuration example for Plesk

Plesk configuration example:

create file on Plesk server /usr/local/psa/admin/conf/templates/custom/domain/nginxDomainVirtualHost.php
copy contents of default file /usr/local/psa/admin/conf/templates/default/domain/nginxDomainVirtualHost.php to file you created

add the following content at the end of the file before the last closing "}" symbol:

<?php if (!$VAR->domain->physicalHosting->proxySettings['nginxProxyMode'] && is_dir($VAR->domain->physicalHosting->httpDir.'/sitepro')): ?>
location ~ /(\.ht|error_log|php_errors\.log)|^/sitepro/(vendor/|src/) {
        deny  all;
}
location ~ ^/ {
        index index.php index.html;
        try_files /sitepro$uri /sitepro$uri/ /sitepro/index.php?$args;
}
<?php endif; ?>

This template will add Site.pro required rules to all clients' sites nginx configuration if the site was published with Site.pro builder.
You can read more about Plesk template files here:
https://docs.plesk.com/en-US/onyx/advanced-administration-guide-linux/virtual-hosts-configuration/changing-virtual-hosts-settings-using-configuration-templates.68693/.