protected function fallbackAuthenticate($data, HTTPRequest $request)
    {
        // Set Email from Login
        if (array_key_exists('Login', $data) && !array_key_exists('Email', $data)) {
            $data['Email'] = $data['Login'];
        }
        $authenticatorClass = Config::inst()->get(self::class, 'fallback_authenticator_class');
        if ($authenticator = Injector::inst()->get($authenticatorClass)) {
            $result = call_user_func(
                [
                    $authenticator,
                    'authenticate'
                ],
                $data,
                $request
            );
            return $result;
        }
    }