diff --git a/src/Service/RisingTideGateway.php b/src/Service/RisingTideGateway.php
index 7eabb251..38276619 100644
--- a/src/Service/RisingTideGateway.php
+++ b/src/Service/RisingTideGateway.php
@@ -59,7 +59,7 @@ class RisingTideGateway
             'body' => $message,
             'date' => $date_string,
             'usagetype' => $this->usage_type,
-            'delivery_receipt_url' => $dr_url,
+            'delivery_receipt_url' => $this->dr_url,
         ];
         error_log(print_r($data, true));