diff --git a/src/RestException.php b/src/RestException.php
index 42913816..d38cc962 100644
--- a/src/RestException.php
+++ b/src/RestException.php
@@ -86,6 +86,9 @@ public function __construct($httpStatusCode, $errorMessage = null, array $detail
             $this->stage = $previous ? $events[count($events)-2] : end($events);
         }
         $this->details = $details;
+        if (is_null($errorMessage)) {
+            $errorMessage = '';
+        }
         parent::__construct($errorMessage, $httpStatusCode, $previous);
     }