btinternet.com Blocking Email: Bad Reputation

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[9545]: CDB04182C4BA: to=<[email protected]> relay=mx.bt.lon5.cpcloud.co.uk[65.20.0.49]:25, delay=159823, delays=159823/0.02/0.11/0, dsn=4.0.0, status=deferred (host mx.bt.lon5.cpcloud.co.uk[65.20.0.49] refused to talk to me: …