diff --git a/roles/base/tasks/postfix.yml b/roles/base/tasks/postfix.yml
index 9b0c1cfd49..747b4159d8 100644
--- a/roles/base/tasks/postfix.yml
+++ b/roles/base/tasks/postfix.yml
@@ -22,7 +22,7 @@
     - "postfix/master.cf/master.cf.{{ host_group }}"
     - "postfix/master.cf/master.cf.{{ postfix_group }}"
     - "postfix/master.cf/master.cf"
-  when: inventory_hostname.startswith('smtp-mm') or "'mailman' in group_names"
+  when: inventory_hostname.startswith('smtp-mm') or inventory_hostname.startswith('mailman')
   notify:
   - restart postfix
   tags: