Google Assistant - Manuel Setup

Configuration Voice Assistant
1

Hi everyone,

I’m trying to set up Google Assistant integration with Home Assistant by following the official documentation: Google Assistant - Home Assistant

I’ve completed Step 5 (Google Cloud Platform configuration) exactly as described, but I’m stuck when adding the app in the Google Home App.

After signing in to Home Assistant with my credentials in the Google Home App, I get:

Could not reach [test] Home Assistant. Please try again.

My Setup:

  • Installation method: Home Assistant Container
  • Core: 2026.9.1
  • Frontend: 20260826.6
  • Domain: mydomain.com:8123 (accessible externally via HTTPS)
  • Port: 8123 (no reverse proxy)

When testing the required endpoints manually, I get the following responses:
mydomain:8123/auth/authorize → Invalid redirect URI (:white_check_mark: expected when not providing redirect URI like oauth-redirect.googleusercontent)
mydomain:8123/auth/token → 405: Method Not Allowed
mydomain:8123/api/google_assistant → 405: Method Not Allowed

Are these responses expected? The documentation doesn’t explicitly mention what to expect when manually testing these endpoints.

  • I found this old thread, along with many others, with users experiencing the same issue, but the solutions seem outdated or aren’t covered in the current documentation.
  • My SSL certificate (Let’s Encrypt) is valid for mydomain.com and works on Port 8123.

Is there a way to check why Google Home cannot reach my Home Assistant insallation? I can access my Home Installation from outside my local network.

Thanks in advance for any help!
Let me know if you need more details.

2

Not a direct answer to your problem, but there is a way to expose HA to Glloe Home without exposing your instance to the cloud this way. You can also use Matter Hub and expose all devices locally via Matter. Setup is quite simple.