diff --git a/app/UI/Sign/SignPresenter.php b/app/UI/Sign/SignPresenter.php
index 9989eb2..3ad9da2 100644
--- a/app/UI/Sign/SignPresenter.php
+++ b/app/UI/Sign/SignPresenter.php
@@ -44,6 +44,7 @@ class SignPresenter extends Presenter
             $this->redirect('Faktura:');
 
         } catch (AuthenticationException $e) {
+            error_log('Kufrik - neplatne prihlaseni.', 0); // log je ve var/log/apache2/error.log (fail2ban)
             $form->addError('Nespravný e-mail nebo heslo.');
         }
     }