I have had Google Calendar working for ages. I was doing something unrelated with Google and decided to clean up unused projects in the Google Developers Console. Of course I extended that to deleting the one I needed, and so obviously my calendars broke. The log was showing “deleted_client: The OAuth client was deleted”.
I created a new project, got the oAuth details, updated the config and rebooted. But I was still getting the same error. I copied it all to another HA instance on a different machine, and it worked. Some Googling suggested deleting “.google.token”. After doing so, I was pretty sure it was working that day (the token file got created again), but maybe I just checked the error went away. But as of now, it’s not working.
Further Googling suggested reusing the client id on two instances was a problem, so I created another one. I ensured that the token file was deleted along with any previous “google_calendars.yaml”, copied in the new client id and secret, and then restarted HA.
But still no go, and there is nothing in the log. Pulling my hair out now!