Can't Link Google Nest Integration - "Can't link to [Project Name]" Error

Third party integrations
1

Hi everyone,

I’m trying to set up the Google Nest integration in Home Assistant but keep getting a “Can’t link to [Project Name]” error. I’ve gone through all the standard troubleshooting and everything appears to be configured correctly, but it still won’t connect.

My setup:

  • Home Assistant version: 2025.12.5
  • Running in Docker on Ubuntu 24.04
  • Google Cloud Project ID: fluid-kiln-408401
  • Device Access Project IDs: I have 3 existing projects (already paid the $5 fee previously)

What I’ve verified:

  • OAuth 2.0 Client configured correctly in Google Cloud Console
  • Authorized JavaScript origins: https://my.home-assistant.io
  • Authorized redirect URIs: https://my.home-assistant.io/redirect/oauth
  • OAuth Client ID is linked in the Device Access Project
  • Tried multiple Device Access Project IDs - all give the same error

Steps I’ve taken:

  1. Navigate to Settings → Devices & Services → Add Integration → Nest
  2. Enter Cloud Project ID: fluid-kiln-408401
  3. Enter Device Access Project ID: (tried all 3 of mine)
  4. Get error: “Can’t link to [Project Name]. Please contact [Project Name] if the issue persists”

The OAuth configuration was just updated, so it might be a propagation delay, but I wanted to check if there’s anything else I should verify or if this is a known issue with the current version.

Any suggestions would be appreciated!
TIA
John

2

I’m having a similar issue with integrations that were already set up. My google calendar, nest and keep sync are all not working currently. Was there an update on Google’s side?