diff --git a/docs/security/tls.md b/docs/security/tls.md
index 829568a..53de4fd 100644
--- a/docs/security/tls.md
+++ b/docs/security/tls.md
@@ -222,7 +222,7 @@ All files (certs/keys) are then available under /root/.acme.sh/{hostname} (you'l
 ##### For DNS challenges (existing records)
 For each cert/dns record, we have to ask for a renewal
 ```
-acme.sh --renew-all 
+acme.sh --renew-all --dnssleep 3 
 ```
 
 ##### For HTTP challenges