Google Device Access - Get and Access Token - Unauthorized - google-cloud-platform

Question

I am trying to get setup so that I can view my Nest equipment on my home automation system. Now with the Google Device Access, I have multiple steps that must be completed. I have created the project in Device Access. I setup the OAuth2 credentials. I enabled the api in the Google Cloud Portal. I "linked" the account / OAuth2 cred to my project to get the "authorization-code".
Now I am failing to "Get an Access Token".
When I try to use Google's Template and fill in the OAuth2-Client-ID, OAuth-Client-Secret and Authorization Code, the copy/paste it into a terminal session, I get: "curl: (3) URL using bad/illegal format or missing URL".
If instead I create my curl statement myself, using the data, I get '{
"error": "invalid_client",
"error_description": "Unauthorized"
}'
How do I get to the next step to get an Access Token?

Answer 1

I just had the same problem. The curl command automatically generated on the Google instruction page https://developers.google.com/nest/device-access/authorize did not work.
From Google (and not working) :-
curl -L -X POST 'https://www.googleapis.com/oauth2/v4/token?
client_id=oauth2-client-id&
client_secret=oauth2-client-secret&
code=authorization-code&
grant_type=authorization_code&
redirect_uri=https://www.google.com'
This did work:-
curl -L -X POST 'https://www.googleapis.com/oauth2/v4/token?' -d 'client_id=oauth2-client-id' -d 'client_secret=oauth2-client-secret' -d 'code=authorization-code' -d 'grant_type=authorization_code' -d 'redirect_uri=https://www.google.com'
Just replace oauth2-client-id, oauth2-client-secret, authorization-code with your values.
If the requested access token is not passed back to you and you get this response instead :-
{
"error": "invalid_grant",
"error_description": "Bad Request"
}
This means the authorisation code has been used or has been passed in a request that failed and you need to regenerate the device authorisation code - the authorisation_code in the curl request - using the same process you followed to get it the first time.