diff --git a/monitoring/nagios.py b/monitoring/nagios.py
index ee67a3ae20b..b55a374b34f 100644
--- a/monitoring/nagios.py
+++ b/monitoring/nagios.py
@@ -266,7 +266,7 @@ def main():
             module.fail_json(msg='no command passed for command action')
     ##################################################################
     if not cmdfile:
-        module.fail_json('unable to locate nagios.cfg')
+        module.fail_json(msg='unable to locate nagios.cfg')
 
     ##################################################################
     ansible_nagios = Nagios(module, **module.params)