nginxproxy 설정 부분에서 질문있습니다!

version: "3"

services:
  nginxproxy:
    depends_on:
      - client
    image: nginx:latest
    ports:
      - "80:80"
      - "443:443"
    restart: always
    volumes:
      - ./nginx/nginx.conf:/etc/nginx/nginx.conf
      - ./certbot-etc:/etc/letsencrypt
      - ./myweb:/usr/share/nginx/html
    container_name: nginxproxy

  certbot:
    depends_on:
     - nginxproxy
     - client
    image: certbot/certbot
    container_name: certbot
    volumes:
      - ./certbot-etc:/etc/letsencrypt
      - ./myweb:/usr/share/nginx/html
    command: certonly --webroot --webroot-path=/usr/share/nginx/html --email example@gamil.com --agree-tos --no-eff-email --keep-until-expiring -d example.com -d www.example.com

  front:
    restart: always
    build:
      context: /home/ubuntu/client
      dockerfile: Dockerfile
    ports:
      - "4000:80" # if want direct access
    container_name: client

upstream docker-client {
        server front:4000;
    }


server {
        listen 80;
        server_name example.com www.example.com;

        location ~ /.well-known/acme-challenge {
                allow all;
                root /usr/share/nginx/html;
                try_files $uri =404;
                #try_files $uri /index.tsx;
        }

        # Redirection
        location / {
                return 301 https://$host$request_uri;
        }
    }

server {
        listen 443 ssl;
        server_name example.com www.example.com;

        ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
        ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
        include /etc/letsencrypt/options-ssl-nginx.conf;
        ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;

        proxy_connect_timeout 1d;
        proxy_send_timeout 1d;
        proxy_read_timeout 1d;

        location /client/ {
            proxy_pass         http://docker-client;
            proxy_http_version 1.1;
            proxy_redirect     off;
            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-Host $server_name;
            proxy_set_header   X-Forwarded-Proto $scheme;
       }

2. client Browser 에서 http://example.com 으로 요청했을 때

3. 예상되는 결과는 아래와 같습니다.

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4. 그러나 결과적으로 정상적으로 요청이 처리되고 있는데

제가 놓치고 있는 부분이 어디인지 알 수있을까요?

+ upstream 부분을 아래로 바꾸어도 정상동작합니다

upstream docker-client {
        server front;
    }