diff --git a/en_US/howto/2-quarantining.md b/en_US/howto/2-quarantining.md
index 73ac8190..480ea66e 100644
--- a/en_US/howto/2-quarantining.md
+++ b/en_US/howto/2-quarantining.md
@@ -135,6 +135,9 @@ NOTIFICATION_SMTP_DEBUG_LEVEL = 0
 # URL of your iRedAdmin-Pro login page which will be shown in notification
 # email, so that user can login to manage quarantined emails.
 # Sample: 'https://your_server.com/iredadmin/'
+#
+# Note: mail domain must have self-service enabled, otherwise normal
+#       mail user cannot login to iRedAdmin-Pro for self-service.
 NOTIFICATION_URL_SELF_SERVICE = 'https://[your_server]/iredadmin/'
 
 # Subject of notification email. Available placeholders:
diff --git a/html/quarantining.html b/html/quarantining.html
index 7b8fb2a4..2dc9222a 100644
--- a/html/quarantining.html
+++ b/html/quarantining.html
@@ -149,6 +149,9 @@ NOTIFICATION_SMTP_DEBUG_LEVEL = 0
 # URL of your iRedAdmin-Pro login page which will be shown in notification
 # email, so that user can login to manage quarantined emails.
 # Sample: 'https://your_server.com/iredadmin/'
+#
+# Note: mail domain must have self-service enabled, otherwise normal
+#       mail user cannot login to iRedAdmin-Pro for self-service.
 NOTIFICATION_URL_SELF_SERVICE = 'https://[your_server]/iredadmin/'
 
 # Subject of notification email. Available placeholders: