diff --git a/config/mail.php b/config/mail.php
index 07342fc43b0..df13d3df226 100644
--- a/config/mail.php
+++ b/config/mail.php
@@ -46,7 +46,7 @@
             'username' => env('MAIL_USERNAME'),
             'password' => env('MAIL_PASSWORD'),
             'timeout' => null,
-            'local_domain' => env('MAIL_EHLO_DOMAIN'),
+            'local_domain' => env('MAIL_EHLO_DOMAIN', parse_url(env('APP_URL', 'http://localhost'), PHP_URL_HOST)),
         ],
 
         'ses' => [