diff --git a/certbot-postfix/certbot_postfix/installer.py b/certbot-postfix/certbot_postfix/installer.py
index 910fa67a6..94cfa3194 100644
--- a/certbot-postfix/certbot_postfix/installer.py
+++ b/certbot-postfix/certbot_postfix/installer.py
@@ -47,6 +47,7 @@ class Installer(plugins_common.Installer):
         Finish up any additional initialization.
 
         :raises errors.PluginError: when an unexpected error occurs
+        :raises errors.MisconfigurationError: when the config is invalid
         :raises errors.NoInstallationError: when can't find installation
         :raises errors.NotSupportedError: when version is not supported