diff --git a/modules/recurring_events_registration/src/Form/RegistrantForm.php b/modules/recurring_events_registration/src/Form/RegistrantForm.php
index cbf49452ae5a73bde479eea84aed9d5422f8878c..ae71fb670d5d170979811961f73a5c6cbf900e9f 100644
--- a/modules/recurring_events_registration/src/Form/RegistrantForm.php
+++ b/modules/recurring_events_registration/src/Form/RegistrantForm.php
@@ -14,6 +14,7 @@ use Drupal\Core\Entity\EntityFieldManager;
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Cache\CacheTagsInvalidatorInterface;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 
 /**
  * Form controller for Registrant edit forms.