Hi @e.stallcup,
Welcome to the Auth0 Community!
I understand you have questions about redirecting users after them denying registration.
Unfortunately, this is not possible with a Pre-User Registration Action, as you have observed.
For now, only the Post-Login Action allows for user redirection. In this scenario, there are a couple of options moving forward.
First, when using the Pre-User Registration, there is an option to specify the reason and user message in the api.access.deny(reason, userMessage) method, which could explain to the user why they were denied registration.
Or the second option is to use the Post-Login Action to deny the user access and then redirect them to your custom-hosted page. This is the approach I would recommend for your use case.
Understandably, this will prevent user login and increment the number of users in your database, which may warrant some degree of grooming. However, this will not affect your MAU (Monthly Active Users) count since these users never successfully “logged in”.
I hope this helps!
Please let me know how this works for you or if you have any additional questions.
Thanks,
Rueben