qb_akkoma/lib/pleroma/web/oauth/fallback_controller.ex

defmodule Pleroma.Web.OAuth.FallbackController do
  use Pleroma.Web, :controller
  alias Pleroma.Web.OAuth.OAuthController

  # No user/password
  def call(conn, _) do
    conn
    |> put_flash(:error, "Invalid Username/Password")
    |> OAuthController.authorize(conn.params)
  end
end