diff --git a/docs/add-roundcube.rst b/docs/add-roundcube.rst
index 4e6be83..6b10d5b 100644
--- a/docs/add-roundcube.rst
+++ b/docs/add-roundcube.rst
@@ -20,7 +20,7 @@ servers may require more work.
         extraConfig = ''
           # starttls needed for authentication, so the fqdn required to match
           # the certificate
-          $config['smtp_server'] = "tls://${config.mailserver.fqdn}";
+          $config['smtp_host'] = "tls://${config.mailserver.fqdn}";
           $config['smtp_user'] = "%u";
           $config['smtp_pass'] = "%p";
         '';