Vhost docker website resolves with port at the end but nginx 502 error without it (recv failed Connection reset by peer)

Question

It's an email server that everyone else seems to be getting running with the same settings. For some reason it's not working for me, and none of the previous answers for "502 nginx docker" or "recv failed Connection reset by peer" have solved it. Maybe it has to do with my Nginx Vhost setup?

The site loads properly on serverIP:5870 and if I change proxy_pass http://127.0.0.1:5870; to proxy_pass http://example.com:5870; then it will load on example.com:5870. But it gives the 502 error when I visit the site without the port.

If I set proxy_pass http://127.0.0.1:5870; and visit example.com:5870 I get:

The connection for this site is not secure
example.com sent an invalid response.
Try running Windows Network Diagnostics.
ERR_SSL_PROTOCOL_ERROR

If I change proxy_pass to http://example.com:5870; example.com will load, but a "broken" page with basic text and the urls are http://localhost:9000/subscription/form".

Broken listmonk homepage image

docker-compose.yml:

version: "3.7"

x-app-defaults: &app-defaults
  restart: unless-stopped
  image: listmonk/listmonk:latest
  ports:
    - "5870:9000"
  networks:
    - listmonk
  environment:
    - TZ=Etc/UTC

x-db-defaults: &db-defaults
  image: postgres:13
  ports:
    - "9432:5432"
  networks:
    - listmonk
  environment:
    - POSTGRES_PASSWORD=pw
    - POSTGRES_USER=listmonk
    - POSTGRES_DB=listmonk
  restart: unless-stopped
  healthcheck:
    test: ["CMD-SHELL", "pg_isready -U listmonk"]
    interval: 10s
    timeout: 5s
    retries: 6

services:
  db:
    <<: *db-defaults
    container_name: listmonk_db
    volumes:
      - type: volume
        source: listmonk-data
        target: /var/lib/postgresql/data

  app:
    <<: *app-defaults
    container_name: listmonk_app
    depends_on:
      - db
    volumes:
      - ./config.toml:/listmonk/config.toml
      - ./uploads:/listmonk/uploads

networks:
  listmonk:

volumes:
  listmonk-data:

nginx config:

server {
        listen              443 ssl;
        server_name            example.com;

  location / {
     proxy_pass  http://127.0.0.1:5870;
     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; 
    }

}

server {
    listen              80;
    server_name            example.com;
      location / {
return 301 https://$host$request_uri;
      }
}

The nginx error log shows 2023/11/22 17:54:00 [error] 54579#54579: *2 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: <myip>, server: example.com, request: "GET / HTTP/2.0", upstream: "http://127.0.0.1:5870/", host: "example.com"

Search results for "recv failed 104 Connection reset by peer while reading response header from upstream" all say it's a php-fpm issue. But I haven't found any solutions. php-fpm:

sudo netstat -nlpt |grep 9000
tcp        0      0 127.0.0.1:9000          0.0.0.0:*               LISTEN      1175/php-fpm: maste

I've tried many variations of proxy_pass:

• proxy_pass http://example.com:5870;
• proxy_pass http://<SERVER_IP>:5870; - same result as above.
• proxy_pass http://0.0.0.0:5870; same as 127.0.0.1:5870.
• proxy_pass http://example.com/; results in "ERR_TOO_MANY_REDIRECTS".
• proxy_pass http://listmonk_app:5870;, proxy_pass http://app:5870;, and proxy_pass http://listmonk:5870; all cause nginx errors.

I found this nginx resolving localhost on proxy pass and ran:

curl 127.0.0.1:5870
curl: (56) Recv failure: Connection reset by peer

curl 0.0.0.0:5870
curl: (56) Recv failure: Connection reset by peer

curl 127.0.0.1:9000
curl: (56) Recv failure: Connection reset by peer

docker ps
CONTAINER ID   IMAGE                      COMMAND                  CREATED       STATUS                  PORTS                                       NAMES
6738da252977   listmonk/listmonk:latest   "./listmonk"             3 weeks ago   Up 47 hours             0.0.0.0:5870->9000/tcp, :::5870->9000/tcp   listmonk_app
f8d43916e568   postgres:13                "docker-entrypoint.s…"   3 weeks ago   Up 47 hours (healthy)   0.0.0.0:9432->5432/tcp, :::9432->5432/tcp   listmonk_db

sudo netstat -nlpt |grep 5870
tcp        0      0 0.0.0.0:5870            0.0.0.0:*               LISTEN      2757/docker-proxy
tcp6       0      0 :::5870                 :::*                    LISTEN      2762/docker-proxy

I tried some of the solutions here https://serverfault.com/questions/351212/nginx-redirects-to-port-8080-when-accessing-url-without-slash

proxy_set_header Host $host:$server_port; didn't seem to change anything.

I also tried

  proxy_pass http://example.com:5870/;
  proxy_redirect http://example.com:5870/ http://example.com/;

Maybe this NodeJs on nginx not working without a port number in the url is the answer, but I don't understand it.

Answer 1

It was a firewall issue. I disabled my firewall and it works.