Community Auth Add User Registration Error

I am not sure if this is an "issue". Currently I think there is no way to distinguish between if the login user is registered or not and failed login attempt by mismatched username/password.

So the community auth will treat them as the same, and try to count the invalid login attempt.

I wonder if we could add the support for this, or if there is an existing solution. please correct me if I was wrong.

Thank you so much in advance.