diff --git a/core/lib/Drupal/Core/ParamConverter/AdminPathConfigEntityConverter.php b/core/lib/Drupal/Core/ParamConverter/AdminPathConfigEntityConverter.php
index 17dedd1..45a6c61 100644
--- a/core/lib/Drupal/Core/ParamConverter/AdminPathConfigEntityConverter.php
+++ b/core/lib/Drupal/Core/ParamConverter/AdminPathConfigEntityConverter.php
@@ -71,7 +71,7 @@ public function convert($value, $definition, $name, array $defaults, Request $re
     if (strpos($definition['type'], 'entity:{') === 0) {
       $entity_type = $this->entityManager->getDefinition($entity_type_id);
       if (!$entity_type->isSubclassOf('\Drupal\Core\Config\Entity\ConfigEntityInterface')) {
-        return NULL;
+        return parent::convert($value, $definition, $name, $defaults, $request);
       }
     }