Nginx unexpectedly closes connection

[Menelion]

I'm definitely missing something. I'm trying to run a three-container setup first in my local WSL and then transfer it on production server.

My docker-compose.yml is as follows:

version: '2'

services:
  nginx:
    image: nginx
    restart: always
    container_name: nginx
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - '${DOCKER_STORAGE_DIR}/nginx/conf:/etc/nginx/conf.d'
      - '${DOCKER_STORAGE_DIR}/nginx/vhost:/etc/nginx/vhost.d'
      - '${DOCKER_STORAGE_DIR}/nginx/html:/usr/share/nginx/html'
      - '${DOCKER_STORAGE_DIR}/nginx/certs:/etc/nginx/certs:ro'
      - '${DOCKER_STORAGE_DIR}/nginx/logs:/var/log/nginx'

  docker-gen:
    image: nginxproxy/docker-gen
    restart: always
    container_name: nginx-proxy-gen
    command: -notify-sighup nginx -watch -only-exposed -wait 5s:30s /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
    volumes_from:
      - nginx
    volumes:
      - '${DOCKER_STORAGE_DIR}/nginx/nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl:ro'
      - '/var/run/docker.sock:/tmp/docker.sock:ro'
    labels:
      - 'com.github.jrcs.letsencrypt_nginx_proxy_companion.docker_gen'

  letsencrypt:
    image: nginxproxy/acme-companion
    restart: always
    container_name: nginx-proxy-acme
    environment:
      DEFAULT_EMAIL: ${LETSENCRYPT_EMAIL}
      # It's staging as I'm on local
      ACME_CA_URI: ${LETSENCRYPT_CA_ENDPOINT}
    volumes_from:
      - nginx
    volumes:
      - '${DOCKER_STORAGE_DIR}/nginx/certs:/etc/nginx/certs:rw'
      - '${DOCKER_STORAGE_DIR}/nginx/acme:/etc/acme.sh'
      - '/var/run/docker.sock:/var/run/docker.sock:ro'

  gitlab:
    image: 'gitlab/gitlab-ce:latest'
    restart: always
    hostname: ${GITLAB_HOST_NAME}
    container_name: gitlab
    environment:
      VIRTUAL_HOST: ${GITLAB_HOST_NAME}, www.${GITLAB_HOST_NAME}
      LETSENCRYPT_HOST: ${GITLAB_HOST_NAME}, www.${GITLAB_HOST_NAME}
      LETSENCRYPT_EMAIL: ${LETSENCRYPT_EMAIL}
      GITLAB_OMNIBUS_CONFIG: |
        external_url 'https://${GITLAB_HOST_NAME}'
        gitlab_rails['gitlab_shell_ssh_port'] = ${GITLAB_SHELL_PORT}
    ports:
      - '${GITLAB_SHELL_PORT}:${SYSTEM_SHELL_PORT}'
    volumes:
      - '${DOCKER_STORAGE_DIR}/gitlab/config:/etc/gitlab'
      - '${DOCKER_STORAGE_DIR}/gitlab/logs:/var/log/gitlab'
      - '${DOCKER_STORAGE_DIR}/gitlab/data:/var/opt/gitlab'

networks:
  default:
    name: nginx

The DOCKER_STORAGE_DIR variable is set to /srv/docker.

access.log for Nginx is totally empty (although I tried to access the subdomain several times), and in Nginx's error.log there is really nothing valuable:

2022/12/27 00:02:52 [notice] 1#1: using the "epoll" event method
2022/12/27 00:02:52 [notice] 1#1: nginx/1.23.3
2022/12/27 00:02:52 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6) 
2022/12/27 00:02:52 [notice] 1#1: OS: Linux 5.15.79.1-microsoft-standard-WSL2
2022/12/27 00:02:52 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2022/12/27 00:02:52 [notice] 1#1: start worker processes
2022/12/27 00:02:52 [notice] 1#1: start worker process 20
2022/12/27 00:02:52 [notice] 1#1: start worker process 21
2022/12/27 00:02:52 [notice] 1#1: start worker process 22
2022/12/27 00:02:52 [notice] 1#1: start worker process 23
2022/12/27 00:02:52 [notice] 1#1: start worker process 24
2022/12/27 00:02:52 [notice] 1#1: start worker process 25
2022/12/27 00:02:52 [notice] 1#1: start worker process 26
2022/12/27 00:02:52 [notice] 1#1: start worker process 27
2022/12/27 00:02:53 [notice] 1#1: signal 1 (SIGHUP) received, reconfiguring
2022/12/27 00:02:53 [notice] 1#1: reconfiguring
2022/12/27 00:02:53 [notice] 1#1: using the "epoll" event method
2022/12/27 00:02:53 [notice] 1#1: start worker processes
2022/12/27 00:02:53 [notice] 1#1: start worker process 28
2022/12/27 00:02:53 [notice] 1#1: start worker process 29
2022/12/27 00:02:53 [notice] 1#1: start worker process 30
2022/12/27 00:02:53 [notice] 1#1: start worker process 31
2022/12/27 00:02:53 [notice] 1#1: start worker process 32
2022/12/27 00:02:53 [notice] 1#1: start worker process 33
2022/12/27 00:02:53 [notice] 1#1: start worker process 34
2022/12/27 00:02:53 [notice] 1#1: start worker process 35
2022/12/27 00:02:53 [notice] 20#20: gracefully shutting down
2022/12/27 00:02:53 [notice] 20#20: exiting
2022/12/27 00:02:53 [notice] 20#20: exit
2022/12/27 00:02:53 [notice] 21#21: gracefully shutting down
2022/12/27 00:02:53 [notice] 21#21: exiting
2022/12/27 00:02:53 [notice] 24#24: gracefully shutting down
2022/12/27 00:02:53 [notice] 24#24: exiting
2022/12/27 00:02:53 [notice] 23#23: gracefully shutting down
2022/12/27 00:02:53 [notice] 23#23: exiting
2022/12/27 00:02:53 [notice] 24#24: exit
2022/12/27 00:02:53 [notice] 21#21: exit
2022/12/27 00:02:53 [notice] 23#23: exit
2022/12/27 00:02:53 [notice] 22#22: gracefully shutting down
2022/12/27 00:02:53 [notice] 22#22: exiting
2022/12/27 00:02:53 [notice] 22#22: exit
2022/12/27 00:02:53 [notice] 27#27: gracefully shutting down
2022/12/27 00:02:53 [notice] 25#25: gracefully shutting down
2022/12/27 00:02:53 [notice] 27#27: exiting
2022/12/27 00:02:53 [notice] 25#25: exiting
2022/12/27 00:02:53 [notice] 27#27: exit
2022/12/27 00:02:53 [notice] 25#25: exit
2022/12/27 00:02:53 [notice] 26#26: gracefully shutting down
2022/12/27 00:02:53 [notice] 26#26: exiting
2022/12/27 00:02:53 [notice] 26#26: exit
2022/12/27 00:02:53 [notice] 1#1: signal 17 (SIGCHLD) received from 23
2022/12/27 00:02:53 [notice] 1#1: worker process 23 exited with code 0
2022/12/27 00:02:53 [notice] 1#1: worker process 25 exited with code 0
2022/12/27 00:02:53 [notice] 1#1: signal 29 (SIGIO) received
2022/12/27 00:02:53 [notice] 1#1: signal 17 (SIGCHLD) received from 21
2022/12/27 00:02:53 [notice] 1#1: worker process 21 exited with code 0
2022/12/27 00:02:53 [notice] 1#1: worker process 22 exited with code 0
2022/12/27 00:02:53 [notice] 1#1: worker process 24 exited with code 0
2022/12/27 00:02:53 [notice] 1#1: worker process 26 exited with code 0
2022/12/27 00:02:53 [notice] 1#1: worker process 27 exited with code 0
2022/12/27 00:02:53 [notice] 1#1: signal 29 (SIGIO) received
2022/12/27 00:02:53 [notice] 1#1: signal 17 (SIGCHLD) received from 24
2022/12/27 00:02:53 [notice] 1#1: signal 17 (SIGCHLD) received from 20
2022/12/27 00:02:53 [notice] 1#1: worker process 20 exited with code 0
2022/12/27 00:02:53 [notice] 1#1: signal 29 (SIGIO) received
2022/12/27 00:02:56 [notice] 1#1: signal 1 (SIGHUP) received, reconfiguring
2022/12/27 00:02:56 [notice] 1#1: reconfiguring
2022/12/27 00:02:56 [notice] 1#1: using the "epoll" event method
2022/12/27 00:02:56 [notice] 1#1: start worker processes
2022/12/27 00:02:56 [notice] 1#1: start worker process 36
2022/12/27 00:02:56 [notice] 1#1: start worker process 37
2022/12/27 00:02:56 [notice] 1#1: start worker process 38
2022/12/27 00:02:56 [notice] 1#1: start worker process 39
2022/12/27 00:02:56 [notice] 1#1: start worker process 40
2022/12/27 00:02:56 [notice] 1#1: start worker process 41
2022/12/27 00:02:56 [notice] 1#1: start worker process 42
2022/12/27 00:02:56 [notice] 1#1: start worker process 43
2022/12/27 00:02:56 [notice] 28#28: gracefully shutting down
2022/12/27 00:02:56 [notice] 28#28: exiting
2022/12/27 00:02:56 [notice] 30#30: gracefully shutting down
2022/12/27 00:02:56 [notice] 29#29: gracefully shutting down
2022/12/27 00:02:56 [notice] 30#30: exiting
2022/12/27 00:02:56 [notice] 29#29: exiting
2022/12/27 00:02:56 [notice] 31#31: gracefully shutting down
2022/12/27 00:02:56 [notice] 34#34: gracefully shutting down
2022/12/27 00:02:56 [notice] 28#28: exit
2022/12/27 00:02:56 [notice] 31#31: exiting
2022/12/27 00:02:56 [notice] 34#34: exiting
2022/12/27 00:02:56 [notice] 30#30: exit
2022/12/27 00:02:56 [notice] 29#29: exit
2022/12/27 00:02:56 [notice] 34#34: exit
2022/12/27 00:02:56 [notice] 31#31: exit
2022/12/27 00:02:56 [notice] 33#33: gracefully shutting down
2022/12/27 00:02:56 [notice] 35#35: gracefully shutting down
2022/12/27 00:02:56 [notice] 33#33: exiting
2022/12/27 00:02:56 [notice] 35#35: exiting
2022/12/27 00:02:56 [notice] 32#32: gracefully shutting down
2022/12/27 00:02:56 [notice] 33#33: exit
2022/12/27 00:02:56 [notice] 35#35: exit
2022/12/27 00:02:56 [notice] 32#32: exiting
2022/12/27 00:02:56 [notice] 32#32: exit
2022/12/27 00:02:56 [notice] 1#1: signal 17 (SIGCHLD) received from 30
2022/12/27 00:02:56 [notice] 1#1: worker process 29 exited with code 0
2022/12/27 00:02:56 [notice] 1#1: worker process 30 exited with code 0
2022/12/27 00:02:56 [notice] 1#1: worker process 31 exited with code 0
2022/12/27 00:02:56 [notice] 1#1: worker process 33 exited with code 0
2022/12/27 00:02:56 [notice] 1#1: worker process 34 exited with code 0
2022/12/27 00:02:56 [notice] 1#1: signal 29 (SIGIO) received
2022/12/27 00:02:56 [notice] 1#1: signal 17 (SIGCHLD) received from 28
2022/12/27 00:02:56 [notice] 1#1: worker process 28 exited with code 0
2022/12/27 00:02:56 [notice] 1#1: worker process 35 exited with code 0
2022/12/27 00:02:56 [notice] 1#1: signal 29 (SIGIO) received
2022/12/27 00:02:56 [notice] 1#1: signal 17 (SIGCHLD) received from 32
2022/12/27 00:02:56 [notice] 1#1: worker process 32 exited with code 0
2022/12/27 00:02:56 [notice] 1#1: signal 29 (SIGIO) received
2022/12/27 00:02:56 [notice] 1#1: signal 1 (SIGHUP) received, reconfiguring
2022/12/27 00:02:56 [notice] 1#1: reconfiguring
2022/12/27 00:02:56 [notice] 1#1: using the "epoll" event method
[...]

Any ideas please, why does it stupidly shut down?

Thanks.