I am trying to set up and configure a mail server in which I can receive email however I am not having any luck with Postfix or Exim4. I currently have Exim4 configured and it sends mail fine, however it can't receive. When trying to send mail from my other account (gmail) to an account on my server, I get this reply:
Delivery to the following recipient failed permanently: firstname.lastname@example.org Technical details of permanent failure: Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 Unrouteable address (state 14).
How can I fix this? Is it an MX record problem or Exim4 configuration error?