- Plesk for Linux
Emails sent from a specific mailbox on a Plesk server to an external mail server could not be delivered and are bounced back with the following error message in the body:
PLESK_INFO: Client host rejected: Your message was rejected due to spam filtering.
One of the following messages can be found in /var/log/maillog:
CONFIG_TEXT: mail postfix/smtp: F21C9580BF0: firstname.lastname@example.org , relay=mail.example2.com[203.0.113.2]:25, delay=11, delays=0.08/0/1.5/9.7, dsn= 5.1.7, status=bounced (host mail.example2.com[203.0.113.2] said: 550 5.1.7 <email@example.com>: Sender address rejected: undeliverable address: host mail.example2.com[203.0.113.2] said: 550 5.7.0 Your server hostname [hostname.com] for IP [203.0.113.10] matches a pattern which was abusive in the past.. See http://spamauditor.org/best-practices/check_rev
CONFIG_TEXT: <firstname.lastname@example.org>: host mail.example1.com[188.8.131.52] said:
550-"JunkMail rejected - (example.com) [203.0.113.2]:34390 is in an RBL
on 550-rbl.websitewelcome.com, see Blocked - see 550
CONFIG_TEXT: jdoe postfix/smtp: 73BD4219CF: host mx.example.com[203.0.113.2] refused to talk to me: 554 bosimpinc11 bizsmtp Connection refused. 203.0.113.3 has a poor reputation on Cloudmark Sender Intelligence (CSI). Please visit http://csi.cloudmark.com/reset-request/?ip=203.0.113.3 to request a delisting.
- In some cases, MXToolBox Blacklists checker might report that the domain or its IP address are blacklisted.
The domain/mailbox is blacklisted on the mail server, where emails are being sent. This might occur due to spam activity on a Plesk server.
Note: If you are a domain owner, contact your hosting provider for further assistance.
As a temporary workaround, contact a system administrator of the remote server, that hosts a recipient's mailbox, to add the affected domain to whitelist.
To track down spam sources on a Plesk for Linux server, refer to an appropriate KB article:
Note: This administrative task can be done by Plesk Professional Services team on your behalf. For more information, contact Plesk Professional Services team.