diff --git a/Model/Form/Modifier/AddHousenumberFieldValidation.php b/Model/Form/Modifier/AddHousenumberFieldValidation.php
index 86df650..4727fd7 100644
--- a/Model/Form/Modifier/AddHousenumberFieldValidation.php
+++ b/Model/Form/Modifier/AddHousenumberFieldValidation.php
@@ -5,6 +5,7 @@
 
 namespace Vendic\HyvaCheckoutGoogleAddressAutocomplete\Model\Form\Modifier;
 
+use Hyva\Checkout\Model\Form\EntityFormElementInterface;
 use Hyva\Checkout\Model\Form\EntityFormInterface;
 use Hyva\Checkout\Model\Form\EntityFormModifierInterface;
 
@@ -26,6 +27,10 @@ public function apply(EntityFormInterface $form): EntityFormInterface
             function (EntityFormInterface $form) {
                 $street = $form->getElement('street');
 
+                if (!$street instanceof EntityFormElementInterface) {
+                    return;
+                }
+
                 $relatives = $street->getRelatives();
 
                 // Check if there is only one relative, if not, we don't have a housenumber field