diff --git a/interface/web/mail/form/mail_user.tform.php b/interface/web/mail/form/mail_user.tform.php
index b46e43b98e9c7d9a87ddd0980c5dd7851c6c5fe4..da47041093a5de972a99ebfbdd21fb68d0598ada 100644
--- a/interface/web/mail/form/mail_user.tform.php
+++ b/interface/web/mail/form/mail_user.tform.php
@@ -200,6 +200,7 @@ $form["tabs"]['mailuser'] = array(
 					'type' => 'TOLOWER')
 			),
 			'validators' => array (  0 => array ( 'type' => 'ISEMAIL',
+					'allowempty' => 'y',
 					'errmsg'=> 'sender_cc_error_isemail'),
 			),
 			'default' => '',