diff --git a/sendgrid/http/response.py b/sendgrid/http/response.py
index 5cb61a1d..80e307d3 100644
--- a/sendgrid/http/response.py
+++ b/sendgrid/http/response.py
@@ -2,7 +2,7 @@
 
 
 class HTTPStatus:
-    SUCCESS = range(200, 300)  # Success codes: 200-299
+    SUCCESS = range(200, 400)  # Success codes: 200-399
     CLIENT_ERROR = range(400, 500)  # Client error codes: 400-499
     SERVER_ERROR = range(500, 600)  # Server error codes: 500-599