diff --git a/Classes/Server.php b/Classes/Server.php
index 4f068f1..0daf4c6 100644
--- a/Classes/Server.php
+++ b/Classes/Server.php
@@ -289,7 +289,7 @@ class Server {
         if ($datetime === false) {
             $datetime = \DateTime::createFromFormat('Y-m-d', $date);
         }
-        return ($datetime !== false) && !array_sum($datetime->getLastErrors());
+        return ($datetime !== false) && ($datetime->getLastErrors() !== false);
     }
 
 }