diff --git a/src/Notifynder/Builder/NotifynderBuilder.php b/src/Notifynder/Builder/NotifynderBuilder.php
index 5eb8d61..8becb97 100755
--- a/src/Notifynder/Builder/NotifynderBuilder.php
+++ b/src/Notifynder/Builder/NotifynderBuilder.php
@@ -233,7 +233,7 @@ public function toArray()
             }
         }
 
-        $error = "The fields: ".implode(',', $this->requiredFields)." are required";
+        $error = "The fields: ".implode(',', $this->getRequiredFields())." are required";
         throw new NotificationBuilderException($error);
     }