diff --git a/src/Service/FirebaseNotificationService.php b/src/Service/FirebaseNotificationService.php
index 5e38a5a..fa1324c 100644
--- a/src/Service/FirebaseNotificationService.php
+++ b/src/Service/FirebaseNotificationService.php
@@ -301,7 +301,7 @@ class FirebaseNotificationService {
     }
 
     $responseBody = json_decode($response->getBody());
-    if ($response->getStatusCode() === 200 && $responseBody->failure === 0) {
+    if ($response->getStatusCode() === 200 && !isset($responseBody->failure)) {
       return TRUE;
     }