diff --git a/interface/web/mail/form/mail_user.tform.php b/interface/web/mail/form/mail_user.tform.php
index b46e43b98e9c7d9a87ddd0980c5dd7851c6c5fe4..67330f465860f0c129ea319c1ee8acdbd1429761 100644
--- a/interface/web/mail/form/mail_user.tform.php
+++ b/interface/web/mail/form/mail_user.tform.php
@@ -199,7 +199,8 @@ $form["tabs"]['mailuser'] = array(
 				2 => array( 'event' => 'SAVE',
 					'type' => 'TOLOWER')
 			),
-			'validators' => array (  0 => array ( 'type' => 'ISEMAIL',
+			'validators' => array (  0 => array ( 'type' => 'ISEMAILADDRESS',
+					'allowempty' => 'y',
 					'errmsg'=> 'sender_cc_error_isemail'),
 			),
 			'default' => '',