Hi @JPSCorreia,
Welcome to the Auth0 Community!
Generally, a 404 HTTP response error indicates that the webpage cannot be found. It seems that you may have misconfigured something in your Heroku app deployment.
In this case, I recommend double-checking the values in your app and redeploying the app again.
If the issue persists, could you please capture a HAR file of the events and DM them to me to investigate further?
Thank you.