diff --git a/example.env b/example.env
index 5d58a451..a1d0f520 100644
--- a/example.env
+++ b/example.env
@@ -49,7 +49,8 @@ PROXY_READ_TIMEOUT=
 # Necessary if the upload limit in the frappe application is increased
 CLIENT_MAX_BODY_SIZE=
 
-# List of sites for letsencrypt certificates quoted with backtick (`) and separated by comma (,)
+# Single site: SITES_RULE=Host(`erp.example.com`)
+# Multiple sites: SITES_RULE=Host(`a.example.com`) || Host(`b.example.com`)
 # More https://doc.traefik.io/traefik/routing/routers/#rule
 # About acme https://doc.traefik.io/traefik/https/acme/#domain-definition
-SITES=`erp.example.com`
+SITES_RULE=Host(`erp.example.com`)