diff --git a/core/Piwik.php b/core/Piwik.php
index e2f1733cd45d28f70af60032a2d7a0ff3d073aa4..d5bd08abd32884c2ac7ecd6ef790143ddbc29324 100644
--- a/core/Piwik.php
+++ b/core/Piwik.php
@@ -657,7 +657,7 @@ class Piwik
      */
     public static function isValidEmailString($emailAddress)
     {
-        return (preg_match('/^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9_.-]+\.[a-zA-Z]{2,7}$/D', $emailAddress) > 0);
+        return (preg_match('/^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9_.-]+\.[a-zA-Z]{2,12}$/D', $emailAddress) > 0);
     }
 
     /**