Hi @alexp1,
The link you shared discusses custom parameters within New Universal Login Page Templates. Page Templates are only supported when using the New Universal Login Experience. You mention you are using auth0-js, which indicates that you are using the Classic Login Experience in your application. Can you confirm?
Related docs on passing custom parameters:
- Passing Custom Parameters to Auth0 Actions from Applications
- Passing custom parameters with auth0.js authorize
Thanks,
Mary Beth