Proxy Outpost confusion

[rattencreep]

I have a long standing, working authentik instance on docker host A, behind traefik.
I have a second docker host B, running its own traefik instance.

My goal is, to deploy a proxy outpost on host B, to utilize the forwardauth middleware in traefik and protect some app.

Case I:

After deploying the proxy outpost on host B with the following docker compose:

---
networks:
  proxy:
    external: true

services:
  authentik-proxy:
    image: ghcr.io/goauthentik/proxy
    container_name: authentik-proxy
    ports:
      - 9000:9000
      - 9443:9443
    environment:
      AUTHENTIK_HOST: https://authentik.hostA.tld
      AUTHENTIK_INSECURE: "true"
      AUTHENTIK_TOKEN: sometoken
    labels:
      traefik.enable: true
      traefik.port: 9000
      traefik.http.routers.authentik.rule: Host(`app.hostB.tld`) && PathPrefix(`/outpost.goauthentik.io/`)
      traefik.http.middlewares.authentik.forwardauth.address: http://authentik-proxy:9000/outpost.goauthentik.io/auth/traefik
      traefik.http.middlewares.authentik.forwardauth.trustForwardHeader: true
      traefik.http.middlewares.authentik.forwardauth.authResponseHeaders: X-authentik-username,X-authentik-groups,X-authentik-entitlements,X-authentik-email,X-authentik-name,X-authentik-uid,X-authentik-jwt,X-authentik-meta-jwks,X-authentik-meta-outpost,X-authentik-meta-provider,X-authentik-meta-app,X-authentik-meta-version
    restart: unless-stopped

The log file contains:

event=Loaded config

event=Loaded config from environment

event=Successfully connected websocket
logger=authentik.outpost.ak-ws
outpost=9b6e8b42-7985-47f1-ab2f-70340ac8336d

error=dial tcp [::1]:6379: connect: connection refused
event=failed to setup application
logger=authentik.outpost.proxyv2

event=Starting Metrics server
listen=0.0.0.0:9300
logger=authentik.outpost.metrics

event=Starting HTTP server
listen=0.0.0.0:9000
logger=authentik.outpost.proxyv2

event=Starting HTTPS server
listen=0.0.0.0:9443
logger=authentik.outpost.proxyv2

event=Starting authentik outpost
hash=tagged
logger=authentik.outpost
version=2025.2.4

error=dial tcp [::1]:6379: connect: connection refused
event=failed to setup application

Note the version of the proxy image: 2025.2.4
ghcr.io/goauthentik/proxy is what the documentation suggests.

The admin interface shows this now:

but the outpost on host B does not show up:

Why is the proxy outpost on host B trying to connect to the redis server on host A?

Case II:

Keeping the docker compose, but changing the image tag to ghcr.io/goauthentik/proxy:2025.12.3 results in a different log output:

env_var=POSTGRES_PASSWORD
event=Environment variable not found, using fallback
fallback=
found=false

event=Loaded config
path=inbuilt-default

event=Loaded config from environment

embedded=true
event=Outpost mode
logger=authentik.outpost.ak-api-controller

event=Successfully connected websocket
logger=authentik.outpost.events
outpost=9b6e8b42-7985-47f1-ab2f-70340ac8336d

event=using PostgreSQL session backend
logger=authentik.outpost.proxyv2

error=failed to connect to `user=someuser database=somedatabase`: 127.0.0.1:5432 (localhost): dial error: dial tcp 127.0.0.1:5432: connect: connection refused [::1]:5432 (localhost): dial error: dial tcp [::1]:5432: connect: connection refused

event=Starting Metrics server
listen=0.0.0.0:9300
logger=authentik.outpost.metrics

event=Starting HTTP server
listen=0.0.0.0:9000
logger=authentik.outpost.proxyv2

event=Starting HTTPS server
listen=0.0.0.0:9443
logger=authentik.outpost.proxyv2

event=Starting authentik outpost
hash=tagged
logger=authentik.outpost
version=2025.12.3

error=failed to connect to `user=someuser database=somedatabase`: 127.0.0.1:5432 (localhost): dial error: dial tcp 127.0.0.1:5432: connect: connection refused [::1]:5432 (localhost): dial error: dial tcp [::1]:5432: connect: connection refused

Why is the proxy outpost on host B now trying to connect to the database server on host A?

Do I misunderstand the outpost concept? What can I do to make this work?
Please shed some light into this.
Thank you!