diff --git a/kafka/conn.py b/kafka/conn.py
index 246cab8d6..23edf227b 100644
--- a/kafka/conn.py
+++ b/kafka/conn.py
@@ -506,7 +506,7 @@ def _try_authenticate_plain(self, future):
 
             # The server will send a zero sized message (that is Int32(0)) on success.
             # The connection is closed on failure
-            self._recv_bytes_blocking(4)
+            data = self._recv_bytes_blocking(4)
 
         except ConnectionError as e:
             log.exception("%s: Error receiving reply from server",  self)