Just using the provided quickstart for Angular, by navigating the the quickstart for the application and following the guide that is there, including downloading and using the sample app:
The application runs, the login button prompts for a login on Auth0(after corrected urls in the application settings in Auth0), the login is successful and the user is returned to the sample app.
At this point, the application is calling https://*.auth0.com/oauth/token, and we are receiving {“error”:“access_denied”,“error_description”:“Unauthorized”}, in the Auth0 logs we are getting failed exchange.