[Skunkworks] Help me out mails rejected my my mail server

Am using a linux mail server using POSTFIX and am getting the bellow error from unknown[196.200.16.3]: 554 5.7.1 <zzzz@ddd.org>: Relay access denied; from=<zzzz@gmail.com> to=<zzzz@ddd.orgg> proto=ESMTP helo=< inbound.accesskenya.com> -- Thanks *Ronnie Kilel* ronniekilel@gmail.com *squeaky wheel gets the grease** *