Enable Google Drive API & Authorize Client ID

1. In Google Cloud Platform Console, select the same project as where the service account was created.
2. Go to Navigation Menu > APIs & Services > Enabled APIs & services.



3. Click on +ENABLE APIS AND SERVICES.



4. Search for the Google Drive API and enable it.



5. Go to Google Workspace Admin Console and log in with the same Google Account.
6. Go to Security > Access and data control > API controls.



7. In API controls page, click MANAGE DOMAIN WIDE DELEGATION.



8. Click Add new and add the Client ID from Create Google Service Account.



9. Add "https://www.googleapis.com/auth/drive" to OAuth scope and click AUTHORIZE.