Not sure of it’s relevant here, but I ran into an issue with reauthorizations after the first auth is a problem because the refresh token is returned only after the first authorization. The net effect is that it works until the access token needs to be refreshed (about an hour), then it breaks.
I pushed this change for the nest binding, but may be relevant for Google TTS, too. Note the addition of &prompt=consent to the URL.
Edit: I should note that this problem drove me absolutely crazy for days. I would do a reauth, then it would work for a while, then it would break. Rinse and repeat. Finally figured it out.
