diff --git a/docs/content/setup-docker-mailserver-using-the-script-setup.sh.md b/docs/content/setup-docker-mailserver-using-the-script-setup.sh.md
index c5fcc94f..18563823 100644
--- a/docs/content/setup-docker-mailserver-using-the-script-setup.sh.md
+++ b/docs/content/setup-docker-mailserver-using-the-script-setup.sh.md
@@ -57,7 +57,7 @@ SUBCOMMANDS:
 
   config:
 
-    ./setup.sh config dkim <keysize> (default: 2048)
+    ./setup.sh config dkim <keysize> (default: 2048) <domain.tld> (optional - for LDAP setups)
     ./setup.sh config ssl <fqdn>
 
   relay: