Have a look at your SMTP out logs and investigate whether your public IP has fallen into a black list (Work closely with your ISP on this). - Update all machines in your network with latest Windows service packs ( download from Microsoft.com) - Ensure the machines are installed with antivirus running the latest updates - Ensure mail server (if any ) is properly secured and has no open relays (its best if you have a well configured firewall such as a cyberoam appliance) Having done the above visit the sites such as SORBS, Robtex, Senderbase etc and manually whitelist your IP. On Sat, May 7, 2011 at 1:11 PM, boniface njoroge <bonifacenjoroge5@gmail.com

wrote:

Hi guys we are usin mdaemon as the mail server and since the past two days when sendind mail to public accounts like yahoo the below mail appears.Any clue on what can be wrong. -------------------------------------------------------------------------- MDaemon Delivery Status Notification - http://www.altn.com/dsn/ --------------------------------------------------------------------------

The attached message had PERMANENT fatal delivery errors.

After one or more unsuccessful delivery attempts the attached message has been removed from the MDaemon mail queue on this server. The number and frequency of delivery attempts are determined by local configuration.

-------------------------------------------------------------------------- YOUR MESSAGE WAS NOT DELIVERED TO ONE OR MORE RECIPIENTS _______________________________________________ Skunkworks mailing list Skunkworks@lists.my.co.ke http://lists.my.co.ke/cgi-bin/mailman/listinfo/skunkworks ------------ Skunkworks Rules http://my.co.ke/phpbb/viewtopic.php?f=24&t=94 ------------ Other services @ http://my.co.ke