diff --git a/roles/nagios_server/files/nagios/services/smtp-mm.cfg b/roles/nagios_server/files/nagios/services/smtp-mm.cfg
index 4935b27f89..69978a1475 100644
--- a/roles/nagios_server/files/nagios/services/smtp-mm.cfg
+++ b/roles/nagios_server/files/nagios/services/smtp-mm.cfg
@@ -1,5 +1,5 @@
 define service {
-  hostgroup_name		smtp-mm
+  hostgroup_name		smtp_mm
   service_description		smtp-mm
   check_command			check_smtp
   use				defaulttemplate