The redirect using Actions is more of a temporary redirect to perform some additional actions as part of the authentication flow and by design you’re expected to return to the Action to complete the authentication. It may not be a suitable fit for your use case. There would be a better way, I’m assuming by default after authentication you come back to http://localhost:3000 as an authenticated user (providing the auth was successful).
If you want to redirect the user to a specific url post authentication and it’s static url i.e. it’s always going to be the same for every user you could just bake that into your application e.g. I have a dot net application which is a regular web app. My callback is https://localhost:5001/callback which is handled by the middleware and I return to https://localhost:5001 by default post successful authentication.
I can redirect somewhere else within my app like this:
public async Task Login(string returnUrl = "/Account/UserProfile")
{
await HttpContext.ChallengeAsync("Auth0", new AuthenticationProperties() { RedirectUri = returnUrl });
}
There may be something similar you can do via the SDK that you’re using.