diff --git a/htdocs/core/actions_sendmails.inc.php b/htdocs/core/actions_sendmails.inc.php
index e23d2ce01a9..51484fcce24 100644
--- a/htdocs/core/actions_sendmails.inc.php
+++ b/htdocs/core/actions_sendmails.inc.php
@@ -491,7 +491,12 @@ if (($action == 'send' || $action == 'relance') && !$_POST['addfile'] && !$_POST
 					}
 					else
 					{
-						$mesg .= 'No mail sent. Feature is disabled by option MAIN_DISABLE_ALL_MAILS';
+						$mesg .= $langs->transnoentities('ErrorFailedToSendMail', dol_escape_htmltag($from), dol_escape_htmltag($sendto));;
+						if (!empty($conf->global->MAIN_DISABLE_ALL_MAILS)) {
+							$mesg .= '<br>Feature is disabled by option MAIN_DISABLE_ALL_MAILS';
+						} else {
+							$mesg .= '<br>Unkown Error, please refers to your administrator';
+						}
 					}
 					$mesg .= '</div>';