diff --git a/Synology-NAS-Guide.md b/Synology-NAS-Guide.md
index b723b9f..e23a568 100644
--- a/Synology-NAS-Guide.md
+++ b/Synology-NAS-Guide.md
@@ -47,7 +47,7 @@ Now it's time to create the certificate for your domain:
 $ cd /usr/local/share/acme.sh
 $ export CERT_DOMAIN="your-domain.tld"
 $ export CERT_DNS="dns_cf"
-$ ./acme.sh --issue --home . -d "$CERT_DOMAIN" --dns "$CERT_DNS"
+$ ./acme.sh --issue --server letsencrypt --home . -d "$CERT_DOMAIN" --dns "$CERT_DNS"
 ```
 
 ## Deploy the default certificate