Manual Google Assistant Integration “Request contains an invalid argument”

Hi there,

I’m currently trying to set up the manual Google Assistant integration using the following guide:
https://www.home-assistant.io/integrations/google_assistant/#manual-setup-if-you-dont-have-home-assistant-cloud

After completing all the required steps, when I click Save, I immediately receive the error:

“Request contains an invalid argument”

I found this error mentioned in the guide, but the explanation is unclear to me and the referenced link appears to be outdated:
https://www.home-assistant.io/integrations/google_assistant/#manual-setup-if-you-dont-have-home-assistant-cloud

The guide says to unlink and relink Home Control if the initial sync doesn’t include agent_user_id, but I don’t fully understand:

  • What exactly needs to be unlinked?
  • Where this should be done?
  • Whether this applies to my situation, since my error occurs earlier in the setup process.

Important details:

  • I am setting up Cloud-to-Cloud
  • The error happens when saving the configuration
  • I use an NGINX reverse proxy for secure HTTPS access to my Home Assistant instance
  • I’m unsure whether the reverse proxy setup could be related to this issue

Most solutions I’ve found mention this error occurring later (during request_sync), but in my case it happens during the Cloud-to-Cloud setup itself.

Has anyone experienced this at this stage of the setup?

Thanks in advance!

2 Likes

I have the same problem, always

Request contains an invalid argument

I check everything, but I can’t figure out where is the problem.

If I try to go on Authorization URL as indicated in the instruction https://[yourdomain:port]/auth/authorize, I have this error return

Invalid redirect URI

Someone have any suggestion?

1 Like

Same issue here

Happened to me also when i selected all devices. Switched to Lights only and the integration was created successfully