Dockerized приложение с Nginx (через docker-compose) - ошибка 502 Bad Gateway

Вам необходимо связать веб-сервис с контейнером nginx, docker-compose будет выглядеть так:

services:
  nginx:
    image: nginx:latest
    restart: unless-stopped
    volumes:
      - ./data/nginx/app.conf:/etc/nginx/nginx.conf
      - ./data/nginx/error.log:/etc/nginx/error_log.log
      - ./data/nginx/cache/:/etc/nginx/cache
      - /etc/letsencrypt/:/etc/letsencrypt/
    environment:
      - ENV=production
      - APPLICATION_URL=http://myapp.domain
    ports:
      - 80:80
      - 443:443
    links:
      - web

  web:
      depends_on:
        - nginx
      image: "myapp:0.1.0"
      restart: unless-stopped
      expose:
        - "4000"
      env_file:
        - config/docker.env

Затем обновите data/nginx/app.conf

events {

}

http {
  client_max_body_size 20m;

  proxy_cache_path /etc/nginx/cache keys_zone=one:500m max_size=1000m;

  server {
      proxy_cache one;
      listen 80;
      listen 443 ssl;
      server_name myapp.domain;

      location / {
          proxy_pass http://web:4000;
          rewrite ^/myapp.domain(.*)$ $1 break;
      }

      ssl_certificate /etc/letsencrypt/live/myapp.domain/fullchain.pem;
      ssl_certificate_key /etc/letsencrypt/live/myapp.domain/privkey.pem;
      include /etc/letsencrypt/options-ssl-nginx.conf;
  }
}