Hi @john_inspiren,
Thank you for your response.
To best assist you, could you please clarify how you are creating and testing the database? Is it through the Auth0 Dashboard or the Management API?
Now, note that the realm parameter you use must correspond to the name of the connection on your Tenant.
Additionally, the Try Connection button in your database can sometimes be unreliable for testing. Instead, I strongly recommend calling the /authorize request to your app, or using the Get Started > Try it out button.
Lastly, could you please check if you can register the user on your app via the Universal Login Page?
Thank you.