Hi, I am facing this problem while sending mail to selected domain such as hotmail.com,cisco.com and other.After sending massege to this domains i am getting this bounce back mail. The following recipient(s) could not be reached: vasim_1981@hotmail.com on 11/9/2009 10:35 AM There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <sit-exchs01.sit.com.sa #5.5.0 smtp;550 OU-001 Mail rejected by Windows Live Hotmail for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation problems. If you are not an email/network admin please contact your E-mail/Internet Service Provider for help. Email/network admins, please visit http://postmaster.live.com for email delivery information and support> please let me know how to solve this problem.

Check if they have black listed you or some body from your domain is spamming them. The NDR itself says " Mail rejected by Windows Live Hotmail for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation problems"Call hotmail and see if there is some thing like this.Raj

You can also start from here to see if you are blacklisted. Provide your Server's IP from your mail servers sending mails to internet. http://www.mxtoolbox.com/blacklists.aspx Hope this helps. Thanks.Vishal Ramnani | MCITP - Exchange 2007 | MCSE Messaging | MCTS - Win 2008 Config

First make sure you have valid PTR or reverse DNS record Public Domains such as Hotmail, Yahoo, AOL checks for reverse pointers. also make sure your server is not acting as open relay which might have caused your domain to go under blacklisting. How to troubleshoot mail relay issues in Exchange Server 2003 and in Exchange 2000 Server http://support.microsoft.com/kb/895853/en-us For exchange 2007 http://msexchangeteam.com/archive/2006/12/28/432013.aspx Make sure you have Antispam/Antivirus fucntioning properly also as Vishal mentioned check your ip to make sure you have not blacklisted. You can also get idea by referring below Things to Do When Your Exchange gets Blacklisted http://www.msexchange.org/articles/Exchange-Blacklisted.htmlVinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|