522 IP REPUTATION BAD
I have recently been seeing issues with email servers sending emails to btinternet.com.
See example from postfix log below (I have changed the to email for privacy).
Nov 13 07:40:53 asc postfix/smtp: CDB04182C4BA: to=<[email protected]> relay=mx.bt.lon5.cpcloud.co.uk[220.127.116.11]:25, delay=159823, delays=159823/0.02/0.11/0, dsn=4.0.0, status=deferred (host mx.bt.lon5.cpcloud.co.uk[18.104.22.168] refused to talk to me: 522 IP REPUTATION BAD (please check for IP address listing on reputation services))
I have discovered that they have changed how there emails work and have new spam filtering system in place. After reading this very informative article it looks like BT are now out sourcing there emails to cp.com.
The system BT now uses CP.com MiraCare Secure Messaging Center for its filtering.
How to fix this problem
As with most filtering systems you can get your IP address de-listed from the filter if it shouldn’t be on there.
Use the following link to delist your IP:
In my case the site in question did have issues with a SPAM bot sending out spam and was put on black lists such as Spamhaus.
This was rectified and removed successfully from other black lists however even weeks later this MiraCare Secure Messaging Center still had the sites IP address blacklisted as ‘Bad Reputation’. So this system may take a long to to de-list a previously compromised IP. I put in a delist request and emails are now sending to btinternet.com addresses.
I would recommend to cp.net that they alter there deferred message to give a link to there reputation service so administrators can easily diagnose and de-list, similar to how other filtering services work.