Authentik Embedded Outpost behind Nginx Proxy Manager

[moutasem1989]

I am running Authentik in Docker accessible through https://auth.domain.tld/. I setup Authentik in Nginx Proxy Manager as following:

And as Custom Nginx Configuration:

location / {
  proxy_pass $forward_scheme://$server:$port;
  proxy_http_version 1.1;
  proxy_set_header X-Forwarded-Proto https;
  proxy_set_header X-Forwarded-Port 443;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_set_header X-Real-IP $remote_addr;
  proxy_set_header Host $host;
  proxy_set_header Upgrade $http_upgrade;
  proxy_set_header Connection "Upgrade";
}

My Embedded Outpost Configurations:

log_level: info
docker_labels: null
authentik_host: https://auth.domain.tld/
docker_network: null
container_image: null
docker_map_ports: true
kubernetes_replicas: 1
kubernetes_namespace: default
authentik_host_browser: https://auth.domain.tld
object_naming_template: ak-outpost-%(name)s
authentik_host_insecure: false
kubernetes_json_patches: null
kubernetes_service_type: ClusterIP
kubernetes_image_pull_secrets: []
kubernetes_ingress_class_name: null
kubernetes_disabled_components: []
kubernetes_ingress_annotations: {}
kubernetes_ingress_secret_name: authentik-outpost-tls

I have a couple of services I am trying to setup with Authentik Proxy Authentication. The services running on the same docker network as Authentik, I managed to configure with authentik docker host name and port in NPM configurations:

This works and I am able to Authenticate into the applications successfully.

However, I also have external services that are not connected to Docker Network of Authentik. When using the Authentik Domain instead of its internal hostname proxy_pass https://auth.domain.tld/outpost.goauthentik.io; i get:

In Authentik Container I am getting error=websocket: bad handshake

Can anzone help me find the correct NPM configurations for Authentik to be accessble? I found this guid but implimenting it into NPM did not help.