Finally got it working - followed the directions. No ports to open. Thanks for the recommendations.

Finally got it to work. I think that on a previous try and failure, my credentials were saved while I had gone back and recover everything over. Cleared out the old credentials, started all over and worked!

This is good to know the next time around. Thanks!

Sorry, just realized you meant Nest device support. Yes, per the instructions, and the Google Device page:

" Thermostats

All Google Nest thermostat models are supported in the Device Access program and the API functionality is the same for all models. See the Thermostat device guide for more information.

Supported as in a yellow or green device? No, I’m running virtually off a booted SSD on a PC.

Why is that relevant to my problem? Same software as everyone else and, otherwise, has been running reliably.

I’ve double-checked settings.

I can select the Google Nest Integration. I enter my Cloud Project ID and click Submit with no error. I am then prompted for my Device Access Project ID, which I enter and click submit. I am then presented with a screen from Google saying that it can’t link to project. No other information and no error. Nothing in the home assistance core logs. I’ve double checked the settings and I know that Project ID is correct as it returns the project name that I set, “HA Nest Project”.

Not really sure where to look for issues - any suggestions are appreciated.

Just upgraded to the latest update. Running: Core 2024.3.0 Supervisor 2024.02.1 Operating System 12.0 Frontend 20240306.0