I'm experimenting setting up Wordpress with this architecture:

• Application Load Balancer (no waf right now) fronts a proxy.
• Internally, a proxy acts as a link between the ALB and the Wordpress site.
• Then there is the internal Wordpress site itself. Hosting the site files and plugins.

For now I've only configured Wordpress to use it's own internal dns name as URL. And everything seems to work fine.

When I configure the site_url and site_home in wp-config.php, I loose access to the wordpress admin site. The url changes to something akin to this:

https://example.wordpress.com/wp-admin/internal.dns.com/wp-login.php

And I'm unable to login to the site. My Wordpress config setup with this:

define('WP_HOME', 'internal.dns.com');
define('WP_SITEURL', 'internal.dns.com');

I'm not sure what I need to do to set the Wordpress site domain to the correct url (example.wordpress.com), while still having wp-admin functionality. Any advice is appreciated.