diff --git a/lib/smstools-handler/failed.js b/lib/smstools-handler/failed.js
index 9be6adf..b48527f 100644
--- a/lib/smstools-handler/failed.js
+++ b/lib/smstools-handler/failed.js
@@ -11,5 +11,5 @@ module.exports = async (msgFilename) => {
         return;
     }
 
-    logger.warn('Sent failed detected', { eventType, msgFile: msgFilename, msgFileContent: msg });
+    logger.warn('Sent failed detected', { eventType, msgFile: msgFilename, msgFileContent: (msg || '').toString() });
 };