Configure caddy (Caddyfile) for custom domain

Question

I'm trying to configure the Caddyfile to allow accessing my website build on an Azure virtual machine via custom domain.

Here is my Caddyfile:

DOMAIN_NAME=azuredomain.northeurope.cloudapp.azure.com:80

{$DOMAIN_NAME} {
  # HTTPS options:
  # tls {$TLS_EMAIL}

  # Test HTTPS setup
  # tls {$TLS_EMAIL} {
  #   ca https://acme-staging-v02.api.letsencrypt.org/directory
  # }

  # Removing some headers for improved security:
  header / -Server

  # Serves static files, should be the same as `STATIC_ROOT` setting:
  root /var/www/django

  # Serving dynamic requests:
  proxy / django:8000 {
    except /static /media
    transparent
    websocket
  }

  # Allows to use `.gz` files when available:
  gzip

  # Logs:
  log stdout
  errors stdout
}

I have created 2 CNAME in my custom domain, which is subdomain.domain.com:

www.subdomain.domain.com.   600 CNAME   
azuredomain.northeurope.cloudapp.azure.com
 
subdomain.domain.com.   600 CNAME   
azuredomain.northeurope.cloudapp.azure.com

I can access the website from azuredomain.northeurope.cloudapp.azure.com, but not from my custom domain: subdomain.domain.com

The error I get is:

404 Site subdomain.domain.com is not served on this interface

nslookup subdomain.domain.com

Gives:

Non-authoritative answer:
subdomain.domain.com       canonical name = azuredomain.northeurope.cloudapp.azure.com
Name:   azuredomain.northeurope.cloudapp.azure.com
Address: <I have hidden the address for privacy concenrs>

I don't understand what I'm doing wrong here. How can I access the website build on azure from my custom domain?