jellyfin NPM https - no images in local network

[deadcxap]

The essence of the problem: I have a nas UNRAID installation, Jellyfin and Nginx Proxy Manager containers are installed. Nas is connected to the router, the provider gives me a fixed external IP, my domain is linked to it. Ports 80 and 443 were forwarded to NPM on router, a subdomain was configured to access jellyfin from the Internet, in the jf configuration I specified my domain and server ip as a reverse proxy ip (NPM works on it, right?..). I didn’t do in NPM initially no special settings - just added the internal ip and http port jellyfin. But with this setup, I received constant errors when watching together with friends or connecting to the server remotely.
At the same time, other programs on the server worked without problems through NPM - access was available both from within the home network and from an external one. NO PROBLEM.
In search of a solution to the problem, I found official instructions for setting up the nginx config. I tried to implement it through the NPM web interface, but nothing worked. Next, I found the configuration file created by NPM and edited it manually (I checked - this also works, the config does not change, and is read by NPM correctly), adding 3 location sections according to the instructions, plus the specified add_header.
And this is where the problems begin. At random times, pictures simply disappear via links from third-party domains (a form for searching and replacing images for a film). The chrome developer tools indicate that the "Cross-Origin-Resource-Policy" setting is incorrect. Setting this header to "cross-origin" does not solve the problem. Complete removal from the configuration of any mention of Cross-Origin-Resource-Policy and related ones does not solve the problem. Restarting the browser helps, about once in 3 times.
The problem only occurs when connecting from within the local network, and only to the assigned domain. Yes, in theory I can enter http://ip:port when I'm at home... But we assign beautiful domain names just so as not to do this, isn't it?
My nginx config:

Code:

server {
  set $forward_scheme http;
  set $server        "192.168.20.70";
  set $port          8096;
 
listen 8080;
listen [::]:8080;

listen 4443 ssl http2;
listen [::]:4443 ssl http2;


  server_name SUB.MY.DOMAIN;

  # Let's Encrypt SSL
  include conf.d/include/letsencrypt-acme-challenge.conf;
  include conf.d/include/ssl-ciphers.conf;
  ssl_certificate /etc/letsencrypt/live/npm-6/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/npm-6/privkey.pem;

    add_header X-Frame-Options "SAMEORIGIN";
    add_header X-Content-Type-Options "nosniff";

    # COOP/COEP. Disable if you use external plugins/images/assets
    add_header Cross-Origin-Opener-Policy "same-origin" always;
    add_header Cross-Origin-Embedder-Policy "require-corp" always;
    add_header Cross-Origin-Resource-Policy "cross-origin" always;

# Permissions policy. May cause issues on some clients
    add_header Permissions-Policy "accelerometer=(), ambient-light-sensor=(), battery=(), bluetooth=(), camera=(), clipboard-read=(), display-capture=(), document-domain=(), encrypted-media=(), gamepad=(), geolocation=(), gyroscope=(), hid=(), idle-detection=(), interest-cohort=(), keyboard-map=(), local-fonts=(), magnetometer=(), microphone=(), payment=(), publickey-credentials-get=(), serial=(), sync-xhr=(), usb=(), xr-spatial-tracking=()" always;

    # Tell browsers to use per-origin process isolation
    add_header Origin-Agent-Cluster "?1" always;


    # Content Security Policy
    # See: https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP
    # Enforces https content and restricts JS/CSS to origin
    # External Javascript (such as cast_sender.js for Chromecast) must be whitelisted.
    # NOTE: The default CSP headers may cause issues with the webOS app
    add_header Content-Security-Policy "default-src https: data: blob: http://image.tmdb.org; style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline' https://www.gstatic.com https://www.youtube.com blob:; worker-src 'self' blob:; connect-src 'self'; object-src 'none'; frame-ancestors 'self'";


    # Force SSL
    include conf.d/include/force-ssl.conf;

proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $http_connection;
proxy_http_version 1.1;

access_log /config/log/proxy-host-4_access.log proxy;
error_log /config/log/proxy-host-4_error.log warn;

client_max_body_size 20M;

location = / {
        return 302 http://$host/web/;
        return 302 https://$host/web/;
    }

    location / {


        # Proxy main Jellyfin traffic
        proxy_pass http://$server:8096;
        proxy_set_header Host $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 $scheme;
        proxy_set_header X-Forwarded-Protocol $scheme;
        proxy_set_header X-Forwarded-Host $http_host;

        # Disable buffering when the nginx proxy gets very resource heavy upon streaming
        proxy_buffering off;

proxy_set_header Accept-Encoding "";
sub_filter '</body>' '<script plugin="Jellyscrub" version="1.0.0.0" src="/Trickplay/ClientScript"></script>    </body>';
sub_filter_once on;
}

    # location block for /web - This is purely for aesthetics so /web/#!/ works instead of having to go to /web/index.html/#!/
    location = /web/ {
        # Proxy main Jellyfin traffic
        proxy_pass http://$server:8096/web/index.html;
        proxy_set_header Host $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 $scheme;
        proxy_set_header X-Forwarded-Protocol $scheme;
        proxy_set_header X-Forwarded-Host $http_host;

proxy_set_header Accept-Encoding "";
sub_filter '</body>' '<script plugin="Jellyscrub" version="1.0.0.0" src="/Trickplay/ClientScript"></script>    </body>';
sub_filter_once on;
    }

    location /socket {


        # Proxy Jellyfin Websockets traffic
        proxy_pass http://$server:8096;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $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 $scheme;
        proxy_set_header X-Forwarded-Protocol $scheme;
        proxy_set_header X-Forwarded-Host $http_host;
    }



  # Custom
  include /data/nginx/custom/server_proxy[.]conf;
}

I'm already going crazy, I tried everything possible in all possible options, I tried to add different headers according to the recommendations from the chrome developer tool, I tried to add external image domains to the trusted ones above... It doesn't help. Only sometimes the situation became even worse - playback stopped working when subtitles were turned on, for example. Or syncplay starts disconnecting every 10 minutes...