Programmatically authenticate in Auth0

I'm setting up cypress.io to test a react app. I'm trying to programmatically authenticate with Auth0 Lock so I don't have to test their UI. Here are the steps:

1. POST to https://[auth0-domain].com/usernamepassword/login

    client_id: "",
    client_secret: "",
    audience: "audience",
    redirectUri: "http://[auth0-domain].com:8383/callback",
    scope: "openid email crud:all",
    protocol: "oauth2",
    sso: true,
    username: "",
    password: "",
    connection: "conn",
    tenant: "tenant",
    popup: false,
   

2. Collect returned form data

3. POST to https://[auth0-domain].com/login/callback

   wa=wsignin1.0&wresult=token&wctx=metastuff

The first steps works but in the third step I'm able to post to login/callback but I get an HTML page with this error message:

Looks like something went wrong! There could be a misconfiguration in the system or a service outage. We track these errors automatically, but if the problem persists feel free to <a href="https://auth0.com/support" target="_new">contact us</a> with this tracking id: <b>e88e08e43b7cdee78458</b>.<br/>Please try again.

I'm wondering if there is something with Auth0 blocking me from doing this or if I'm not sending the correct data/header.

I ended up using the auth0-js module which calls the auth0 callback. Then I use 'should' to wait for the localStorage to be set:

import auth0 from 'auth0-js';
import url from 'url';

Cypress.Commands.add('login', () => {
  const auth = new auth0.WebAuth({
    audience: 'http://audience',
    domain: 'domain.auth0.com',
    clientID: 'qqqqqqqqqqqq',
    redirectUri: 'http://localhost/callback',
    responseType: 'token id_token',
    scope: 'openid email profile name username groups roles',
    sso: true
  });

  auth.login({username: 'username', password: 'pass'});
  cy.window().its('localStorage.user_profile').should('exist')
});