I am using exchange 2010 SP1, everything was working fine until couple of days back. Suddenly, i am getting below error while sending the email to the below domains. I am using Trend Micro IMSS v7 for replying the emails. Any thoughts, why suddenly i started receiving the below message?
"Can not deliver the message you sent. Will not retry.
The following addresses had delivery problems
<email@example.com> : Reply from cio.gov.bh[18.104.22.168]:
<<< 554 5.7.1 Message refused by DNSBL check. dul.dnsbl.borderware.com / 22.214.171.124 This is an automated message from the mail system. This email has been rejected. The email message was detected as spam."
While 126.96.36.199 is my mailbox IP address, i am aware of the fact that this IP belongs to a public range of IP's but we have built in network with this range already so can't really do anything at the moment.