diff --git a/src/Bundle/ChillMainBundle/Controller/ExportController.php b/src/Bundle/ChillMainBundle/Controller/ExportController.php
index c23ebfda2..08b89e4bb 100644
--- a/src/Bundle/ChillMainBundle/Controller/ExportController.php
+++ b/src/Bundle/ChillMainBundle/Controller/ExportController.php
@@ -632,7 +632,7 @@ class ExportController extends AbstractController
         }
     }
 
-    private function rebuildRawData(string $key): array
+    private function rebuildRawData(?string $key): array
     {
         if (null === $key) {
             throw $this->createNotFoundException('key does not exists');