diff --git a/qds_sdk/connection.py b/qds_sdk/connection.py
index 324c27f5..11893444 100644
--- a/qds_sdk/connection.py
+++ b/qds_sdk/connection.py
@@ -188,15 +188,12 @@ def _handle_error(response):
         elif code == 422:
             sys.stderr.write(response.text + "\n")
             raise ResourceInvalid(response)
-        elif code in (502, 504):
+        elif code in (502, 503, 504):
             sys.stderr.write(response.text + "\n")
             raise RetryWithDelay(response)
         elif code == 449:
             sys.stderr.write(response.text + "\n")
-            raise RetryWithDelay(response, Connection._get_error_message(code))
-        elif code in (429, 503):
-            sys.stderr.write(response.text + "\n")
-            raise AlwaysRetryWithDelay(response, Connection._get_error_message(code))
+            raise RetryWithDelay(response, "Data requested is unavailable. Retrying ...")
         elif 401 <= code < 500:
             sys.stderr.write(response.text + "\n")
             raise ClientError(response)