Mail delivery to particular domains fails with the following error message in
0572C2801E1: [email protected], size=3826, nrcpt=1 (queue active)
0572C2801E1: host mx.example.net refused to talk to me: 554 IP=IP_ADDRESS - A problem occurred. (Ask your postmaster for help or to contact [email protected] to clarify.) (BL)
connect to example.com[203.0.113.2]:25: Connection refused E37F6A0AF5: to=<[email protected]>, relay=none, delay=371, delays=371/0.02/0.02/0, dsn=4.4.1, status=deferred (connect to example.com[203.0.113.2]:25: Connection refused)
3B0F8A08BF: host example.com[203.0.113.2] refused to talk to me: 554 5.7.1 You are not allowed to connect.
CONFIG_TEXT: host example.com[203.0.113.2] refused to talk to me: 554 example.com eaxmple.com 203.0.113.2 found on one or more DNSBLs, see http://postmaster.comcast.net/smtp-error-codes.php#BL000010
Error code 554 means IP-Blocking: A remote mail server is not currently accepting emails from a server IP address. This IP blocking may be due to a previously observed unusual volume of emails at the IP address concerned.
Contact the remote mail server/mail relay server’s administrator.
For more information about a blacklisted mail server, visit this KB article.