NGINX Reverse Proxy Manager + Google Assistant redirect invalid URI


I am trying to configure the Google Assistant integration. Google Assistant - Home Assistant
But every time I attempt to do so, I get to the loginscreen in the Google Home app, enter login credentials, it starts trying to connect, but then I get an error saying “Could not reach

It is basically the same as this post: NGINX Proxy manager with google assistant except, I my log files shows my gateway router ( as being the source IP.

I got this in my configuration.yaml file:

  use_x_forwarded_for: true

And FYI, the HA is accessible remotely through the external URL, which is the same I am using in the google config.
The Google application has been made with English language.
Nginx Reverse Proxy Manager has enabled WebSocket support.