update msging hostname guidelines

Author: nasark

_includes/configuration.md

@@ -54,7 +54,7 @@ Configuring messaging is required for appliance setup. It is recommended to conf
 2. Select **Proceed** and appliance_console will apply the configuration that you have
    requested then restart evmserverd to pick up the changes.
 
-**Note:** It is recommended to use your Fully Qualified Domain Name (FQDN) as the messaging hostname rather than `localhost`
+**Note:** It is recommended to use your Fully Qualified Domain Name (FQDN) as the messaging hostname rather than `localhost`, ensure that a resolvable and reachable non-localhost name entry is present in `/etc/hosts`
 
 ### Configuring a Worker Appliance