diff --git a/src/addons.js b/src/addons.js
index acdd325cd..4837277e2 100644
--- a/src/addons.js
+++ b/src/addons.js
@@ -382,7 +382,8 @@ function setupEmail(app, options, callback) {
         'MAIL_SMTP_SERVER=' + config.mailFqdn(),
         'MAIL_SMTP_PORT=587',
         'MAIL_IMAP_SERVER=' + config.mailFqdn(),
-        'MAIL_IMAP_PORT=993'
+        'MAIL_IMAP_PORT=993',
+        'MAIL_DOMAIN=' + config.fqdn()
     ];
 
     debugApp(app, 'Setting up Email');