Hi Sriram,
Thank you for raising this concern to Google Ads API Team.
With regard to your error below, I am afraid that this is out of our scope already. With this, I would suggest checking the
Google Ads Console to see if these credentials are indeed deleted. However, if you no longer see the client ID and client secret that was used to authenticate, then we suggest that just created a new one by following this
link.
"('deleted_client: The OAuth client was deleted.', {'error': 'deleted_client', 'error_description': 'The OAuth client was deleted.'})"