Ruby-on-Rails: How to get rid of "you are being redirected" page

I am overriding Devise's failure response so that I can set a 401 status code. However, when the user fails to sign in, they are redirected to a page with a "you are being redirected" link. If I remove this :status => 401 from the redirect it works fine.

class CustomFailure < Devise::FailureApp
    def redirect_url
      new_user_session_url(:subdomain => 'secure')
    end

    def respond
        if http_auth?
           http_auth
        else
           store_location!
           flash[:alert] = i18n_message unless flash[:notice]
           redirect_to redirect_url, :status => 401
        end
    end
end

edit

Alternatively I would like to display the flash message and remain on the same page but adding this line of code:

render :text => "unauthorized", :status => 401

causes ruby to complain:

undefined method `render' for #<CustomFailure:0x00000103367f28>

What's happening here?