I am attempting to containerize my python backend that I am hosting on a GCP compute engine instance. I created two containers, one for the backend server and one for nginx reverse proxy. My docker-compose.yml:

services:
  web:
    image: <me>/fastapiwithnginx:latest
    container_name: web
    ports:
      - "8001:8001"
    restart: unless-stopped
    logging:
      driver: "json-file"
      options:
        max-file: "1"
        max-size: "100k"
  
  nginx:
    restart: unless-stopped
    image: nginx
    container_name: nginx
    ports:
      - "443:443"
    environment:
      - CERTBOT_EMAIL=<my-email>
    volumes:
      - ./nginx:/etc/nginx/user_conf.d:ro
    #   - /etc/letsencrypt/:/etc/letsencrypt
    depends_on:
      - web
    logging:
      driver: "json-file"
      options:
        max-size: "100k"
        max-file: "1"

I am able to pull both images in my VM and start containers. I am able to connect to the backend by hitting the ip address at port 8001, but I am unable to connect using my server url. I get a net::ERR_CONNECTION_REFUSED.

My nginx.conf is below:

server {
    listen 443 ssl ;
    listen [::]:443 ssl ;

    root /var/www/html;

    # Add index.php to the list if you are using PHP
    index index.html index.htm index.nginx-debian.html;
    server_name <my-server-url>; # managed by Certbot


    location / {
        proxy_pass http://web:8001;
    }

    ssl_certificate /etc/letsencrypt/live/isgs-server.uow-carbon.org/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/isgs-server.uow-carbon.org/privkey.pem;
}

When I run docker ps -a on my vm, I see the following:

ca318e7b0788   nginx                          "/docker-entrypoint.…"   20 minutes ago   Up 16 seconds             80/tcp, 0.0.0.0:443->443/tcp, :::443->443/tcp   nginx
7cf921b40eab   <me>/fastapiwithnginx:latest   "python app/main.py …"   20 minutes ago   Up 20 minutes             0.0.0.0:8001->8001/tcp, :::8001->8001/tcp       web

Any ideas where I’m going wrong?