I am creating a new Google smart home Action, and step one is to create an OAuth 2.0 server for account linking.
https://developers.google.com/actions/identity/oauth2?oauth=code&hl=ko&refresh=1
I have follow all of the steps on the Google documentation under the Auth code UP UNTIL 'start the authentication flow'. I do not know if this is required or where this code would go, but that is a different topic.
However, there is an error with my Authentication page. Linking is done with my iPhone's Google Home app, currently which has the generated [test] prefix. When I click the [test] MYAPP, the service runs through till the redirection correctly. The webpage closes and informs me 'MYAPP is linked. As soon as this notification disapears, a new notification 'Something went wrong. Try again' appears.
Clicking the [test] MYAPP to link any time afterwards leads to a blank webpage that says 'Account now linked', but the MYAPP does not move to the 'linked' portion of the Google Home app.
https://developers.google.com/actions/smarthome/develop/error-logging
After checking the logs, I was initially getting 'OPEN_AUTH_FAILURE' for days. Now, I am getting 'BACKEND_FAILURE'.
What is the next step? How can I debug this?