Cannot access Dockerized Wordpress via custom domain using Nginx reverse proxy (full setup details inside)

[JoeyFenny]

I have an Ubuntu server 20.04
I have nginx installed on that server (nginx is not dockerized)
There are many docker apps running which nginx is proxying for fine.
I am trying to run Wordpress in a docker container using the official Wordpress image and point my domain to nginx which uses proxy_pass to point it to Wordpress container.
When I spin up my docker container, I can access it fine via the IP address but when I try to access it via my domain, I get a redirect loop.

Here is my setup:

DNS Records

A - @ - X.X.X.X
A - www - X.X.X.X

nginx config

server {
    server_name domain.io www.domain.io;
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/www.domain.io/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/www.domain.io/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

    location / {
        proxy_pass http://127.0.0.1:1234;
    }
}
server {
    if ($host = domain.io) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

    if ($host = www.domain.io) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

    listen 80;
    server_name domain.io www.domain.io;
    return 404; # managed by Certbot
}

docker-compose.yml

version: '3.1'
services:
  wordpress:
    image: wordpress
    restart: always
    ports:
      - 1234:80
    environment:
      WORDPRESS_DB_HOST:
      WORDPRESS_DB_USER:
      WORDPRESS_DB_PASSWORD:
      WORDPRESS_DB_NAME:
    volumes:
      - wordpress:/var/www/html
  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_DATABASE:
      MYSQL_USER:
      MYSQL_PASSWORD:
      MYSQL_RANDOM_ROOT_PASSWORD:
    volumes:
      - db:/var/lib/mysql
volumes:
  wordpress:
  db:

The error I'm getting:

[wglambert]

https://github.com/docker-library/docs/tree/master/wordpress#how-to-use-this-image

When running WordPress with TLS behind a reverse proxy such as NGINX which is responsible for doing TLS termination, be sure to set X-Forwarded-Proto appropriately (see "Using a Reverse Proxy" in "Administration Over SSL" in upstream's documentation). No additional environment variables or configuration should be necessary (this image automatically adds the noted HTTP_X_FORWARDED_PROTO code to wp-config.php if any of the above-noted environment variables are specified).

There's also quite a few past issues on this repo about using nginx as a reverse proxy that might help
#609 (comment)
#552
#652

You could also try asking over at the Docker Community Forums, Docker Community Slack, or Stack Overflow