Forwarding Bounce Mails
When you are using the default local SMTP-Relay and send mails from an email address which can't receive mails (e.g. firstname.lastname@example.org), you won't get error messages (bounces) if your mails could not get delivered.
If you want to get these error message, it's possible to create a local forwarding on your servers. If you want to use this, please send an email to email@example.com with the email address you want to have forwarded and also where it should get forwarded to.