diff --git a/classes/Provider/EventDataProvider.php b/classes/Provider/EventDataProvider.php
index 3a7d30be..4e763107 100644
--- a/classes/Provider/EventDataProvider.php
+++ b/classes/Provider/EventDataProvider.php
@@ -222,7 +222,7 @@ private function getCategoryPageData()
             foreach ($prods as $product) {
                 $contentIds[] = ProductCatalogUtility::makeProductId(
                     $product['id_product'],
-                    $product['id_product_attribute']
+                    $product['id_product_attribute'] ?? null
                 );
             }
         }