issueatlas · · Reply permalink
Check the application type in your Auth0 dashboard: for auth0-spa-js it must be a Single Page Application. A machine-to-machine app cannot be converted to another type, so create a new SPA application and use its client ID; reporters confirmed this cleared the 401. Also verify Allowed Web Origins and Allowed Callback URLs include your app's origin, since misconfigured origins are the other common trigger the maintainers pointed to. Source: https://github.com/auth0/auth0-spa-js/issues/488