diff --git a/src/warden-server/etc/warden-watchdog.conf.tmpl b/src/warden-server/etc/warden-watchdog.conf.tmpl
index 6d3fd3b75c53e2b75966c49f9cbc6364514adc51..c7d56e7643019af9d9ce25b58846fc8c08fd2fad 100644
--- a/src/warden-server/etc/warden-watchdog.conf.tmpl
+++ b/src/warden-server/etc/warden-watchdog.conf.tmpl
@@ -5,7 +5,7 @@
 #-------------------------------------------------------------------------------
 # domain_name - server full domain name
 #-------------------------------------------------------------------------------
-$domain_name = _HOSTNAME_;
+$domain_name = "_HOSTNAME_";
 
 #-------------------------------------------------------------------------------
 # email_subject - ...