Yet another permalink issue :-)

Hi everybody,
I’m new in WP but I’ve understand that many people has issues with “pretty” permalinks.
I’m one of the many! 😀
Hopefully I had googled around and checked may things but the solution doesn’t came, so here to ask for help.

When I ran a “Site Health” I receive a warning about REST API doesn’t working – Unexpected result 404.

What I checked:
– Running on debian 10 LAMP – apache2 rewrite module: Enabled;
– WP dir writeable to “www-data” -> .htaccess is modified every time I change under “Settings-Permalinks”; plugins can install by themself without FTP access;
– Everything works fine with “ugly” permalinks; when I enable “pretty” permalinks the issue appears;
– Everything is last version – No updates underlined;
– WP running a fresh install (v. 5.3.2);
– No funny themes installed: just the defaults;
– Plugins: bbPress, NinjaMotd, PolyLang, WP Cerber Security Antispam & Malware Scan, WP Statistics.

In this situation the Gutemberg block editor run only with “ugly” permalinks.

Follows my apache2 configuration file.

Please note: I’m behind a NGINX reverse proxy (just one public IP, sorry!); follows also config file.

Any suggestion to check is strongly welcome!

Thank you very much!

Francesco

<strong># apache2ctl -M</strong>
Loaded Modules:
 core_module (static)
 so_module (static)
 watchdog_module (static)
 http_module (static)
 log_config_module (static)
 logio_module (static)
 version_module (static)
 unixd_module (static)
 access_compat_module (shared)
 alias_module (shared)
 auth_basic_module (shared)
 authn_core_module (shared)
 authn_file_module (shared)
 authz_core_module (shared)
 authz_host_module (shared)
 authz_user_module (shared)
 autoindex_module (shared)
 deflate_module (shared)
 dir_module (shared)
 env_module (shared)
 filter_module (shared)
 mime_module (shared)
 mpm_prefork_module (shared)
 negotiation_module (shared)
 php7_module (shared)
 reqtimeout_module (shared)
 rewrite_module (shared)
 setenvif_module (shared)
 status_module (shared)

Apache2 site configuration file:
On a linux container: This is the only website on this container

<VirtualHost *:80>
        ServerAdmin [email protected]
        DocumentRoot /var/www/www.mysite.ch/

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

NGINX proxy configuration file:

server {
  listen 443 ssl;
  server_name www.mysite.ch;
  ssl_certificate /etc/letsencrypt/live/mysite.ch/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/mysite.ch/privkey.pem;

  location / {
       gzip                    off;

       proxy_read_timeout      300;
       proxy_connect_timeout   300;
       proxy_redirect          off;

       proxy_set_header        Host                $http_host;
       proxy_set_header        X-Real-IP           $remote_addr;
       proxy_set_header        X-Forwarded-For     $proxy_add_x_forwarded_for;
       proxy_set_header        X-Forwarded-Proto   https;
       proxy_set_header        X-Frame-Options     SAMEORIGIN;

       proxy_pass http://192.168.1.159/; # This is the IP addr of the LXC where WP run
  }
}