Google Assistant SDK Gives "Restricted Client" Error (403)

Configuration Voice Assistant
1

I’ve been trying to connect Home Assistant to my Google Assistant with the eventual plan of turning off my Nest thermostat A/C when the sliding back door is left open – a surprisingly difficult thing to do for something so obvious.

I’ve installed the “Google Assistant SDK” add-on, followed all the instructions to set up the “actions console”, found the Web UI (had to replace the ssl-enabled domain name with IP address to get to port 9324), and clicked on “Get a code from Google here”.

But Google doesn’t like it:

Authorization Error
Error 403: restricted_client

This app is not yet configured to make OAuth requests. To do that, set up the app’s OAuth consent screen in the Google Cloud Console.

Request Details
access_type=offline
o2v=1
response_type=code
redirect_uri=urn:ietf:wg:oauth:2.0:oob
state=8...g
prompt=consent
client_id=2...1-f...d.apps.googleusercontent.com
scope=https://www.googleapis.com/auth/assistant-sdk-prototype

The only things configured in the OAuth consent screen are, according to the documentation, an application name (“Home Assistant”, including the space) and my email address (filled in automatically by Google). I’ve tried filling in other fields, too, but nothing changes.

I have external SSL enabled via port 8123 forwarding on my gateway and DuckDNS+LetsEncrypt.

Any idea what I’m missing?

Update#1: I tried forwarding port 9324 from my gateway so I could use the full domain rather than the IP address. Didn’t change anything.
– Brian

2

I deleted the project and started from scratch. This time it worked.

I think that Google’s config pages sometimes didn’t go to the project I was setting up and I ended up doing configuration on a different one without noticing.

3

Did you have to keep port 9324 open?

4

No. It’s only needed to get the oauth2 token. After that it can, and should, be closed.