The DMARC policy is used by email services to combat spam and malicious activity.

DMARC verifies the actual and specified sender address. If these two addresses do not match, the letter is rejected. Even if the sender mistakenly entered his address incorrectly.

The following error message is saved in the mail logs:

Sept 23 14:23:42 vh12 splogger[28569]: 
1d0RET-0007Qn-0Y <= U=***** P=local S=901

Sept 23 14:23:42 vh12 splogger[28571]:
1d0RET-0007Qn-0Y **
R=dnslookup T=remote_smtp:
SMTP error from remote mail server after end of data:
host []: 550 5.7.1
This message was not accepted due to domain (
owner DMARC policy (RFC 7489)

How does an SMTP server work?

If messages fail DMARC

When sending mail using scripts, the From and Envelope From address may be replaced by mistake. Such a letter is rejected by the server.

To pass checks and improve email deliverability, follow these guidelines:

  • Do not change the sender's address in the settings, if possible. By default, your_login@server_name is entered as the sender.
  • Send mail using SMTP protocol.

If you still have questions, please create a ticket to technical support.