diff --git a/roles/docker-discourse/templates/app.yml.j2 b/roles/docker-discourse/templates/app.yml.j2
index ffc10186..edaac64a 100644
--- a/roles/docker-discourse/templates/app.yml.j2
+++ b/roles/docker-discourse/templates/app.yml.j2
@@ -63,7 +63,7 @@ env:
   ## TODO: The SMTP mail server used to validate new accounts and send notifications
   # SMTP ADDRESS, username, and password are required
   # WARNING the char '#' in SMTP password can cause problems!
-  DISCOURSE_SMTP_ADDRESS:           {{system_email_domain}}
+  DISCOURSE_SMTP_ADDRESS:           {{system_email_host}}
   DISCOURSE_SMTP_PORT:              587
   DISCOURSE_SMTP_USER_NAME:         {{system_email}}
   DISCOURSE_SMTP_PASSWORD:          {{system_email_password}}