diff --git a/core/src/main/scala/org/apache/spark/network/ConnectionManager.scala b/core/src/main/scala/org/apache/spark/network/ConnectionManager.scala
index e47e316599301..2492968d5ca7c 100644
--- a/core/src/main/scala/org/apache/spark/network/ConnectionManager.scala
+++ b/core/src/main/scala/org/apache/spark/network/ConnectionManager.scala
@@ -548,7 +548,7 @@ private[spark] class ConnectionManager(port: Int, conf: SparkConf,
         case e: Exception => {
           logError("Error handling sasl client authentication", e)
           waitingConn.close()
-          throw new IOException("Error evaluating sasl response: " + e)
+          throw new IOException("Error evaluating sasl response: ", e)
         }
       }
     }