diff --git a/inventory/group_vars/copr-stg b/inventory/group_vars/copr-stg
index cb4b968fc7..d7c7be3463 100644
--- a/inventory/group_vars/copr-stg
+++ b/inventory/group_vars/copr-stg
@@ -9,3 +9,4 @@ keygen_host: "172.16.1.6"
 resolvconf: "resolv.conf/cloud"
 
 backend_base_url: "http://copr-be-dev.cloud.fedoraproject.org"
+postfix_maincf: "main.cf.copr"