diff --git a/blueprints/mattermost/template.toml b/blueprints/mattermost/template.toml
index 33b0a2ad..0fea8ece 100644
--- a/blueprints/mattermost/template.toml
+++ b/blueprints/mattermost/template.toml
@@ -3,7 +3,7 @@ main_domain = "${domain}"
 
 [config]
 env = [
-"Domain=mm.example.com",
+"Domain=${main_domain}",
 "POSTGRES_USER=mmuser",
 "POSTGRES_PASSWORD=mmuser_password",
 "POSTGRES_DB=mattermost",