diff --git a/html/includes/graphs/graph.inc.php b/html/includes/graphs/graph.inc.php
index f8a0bc949..3d612f02d 100644
--- a/html/includes/graphs/graph.inc.php
+++ b/html/includes/graphs/graph.inc.php
@@ -38,7 +38,7 @@ $id       = mres($_GET['id']);
 
 if (!$config['allow_unauth_graphs'])
 {
-  if (!$_SESSION['authenticated']) { graph_error("Not authenticated"); exit; }
+  if (!$_SESSION['authenticated']) { graph_error("Session not authenticated"); exit; }
 }
 
 preg_match('/^(?P<type>[A-Za-z0-9]+)_(?P<subtype>.+)/', mres($_GET['type']), $graphtype);