Fetch user profile script callback; how to access error in Auth0Client

I’ve set up a custom social connection and using the fetch user profile script to validate the access token. That’s all working as expected.

If the token is invalid, I want to reject the authentication request and pass a reason back to the client.

I guess I call callback(new ErrorI’reason’)).

What I can’t find is how to access that reason from my Auth0Client.

Any suggestions?