Two things to check on a Bad audience error with node-auth0. One, to call the Management API you have to use the Management API audience, not a custom API audience you created in the dashboard. Two, when granting scopes, the correct name is update:users_app_metadata, not update:users or update:users_metadata. Check the Permissions tab of your API in the dashboard for the full list of valid scopes.

_Source: gh:auth0/node-auth0#787 (Auth0)_