diff --git a/.env.production.sample b/.env.production.sample
index 58b983056..cf08a84b9 100644
--- a/.env.production.sample
+++ b/.env.production.sample
@@ -14,7 +14,8 @@ LOCAL_DOMAIN=example.com
 LOCAL_HTTPS=true
 
 # Use this only if you need to run mastodon on a different domain than the one used for federation.
-# Do not use this unless you know exactly what you are doing.
+# You can read more about this option on https://github.com/tootsuite/documentation/blob/master/Running-Mastodon/Serving_a_different_domain.md
+# DO *NOT* USE THIS UNLESS YOU KNOW *EXACTLY* WHAT YOU ARE DOING.
 # WEB_DOMAIN=mastodon.example.com
 
 # Application secrets