Auto replies are not received by external mail servers

Symptoms

• The auto reply mailbox domain has its DMARC policy set to reject

  "v=DMARC1; p=reject; pct=100"

• Auto replies sent by the local mail server are sent to spam or not delivered at all, with the following error

  550-5.7.26 Unauthenticated email from example.com is not accepted due to 550-5.7.26 domain's DMARC policy.

• Auto replies sent by external mail server are not delivered, with the following logged to plesk_debugYYYYMMDD.log

  Warning: SMTP Exception
  at Unable to call send()(SMTPClientSessionTransport::send line 114)
  at Unable to call send()(PocoMailMessage::Impl::send line 323)
  at sendMail([email protected], [email protected])(MessageProcessor::sendMail line 335)

• External SMTP server users can't send email

  # curl smtp://email-smtp.ap-south-1.amazonaws.com:587 -v --mail-from "XXXXXXXXXXXXX" --mail-rcpt "[email protected]" --ssl -u XXXXXXXXXXXXX:*** -T input.txt -k --anyauth
  ...
  curl: (55) MAIL failed: 501

Cause

Plesk product issue PPPM-12688.

Resolution

Warning: Using a mail client is the only solution that works 100% of the time.

There are 3 possible workarounds for this issue.

• Configure auto replies in a mail client: How to set up auto replies in Outlook.

• Configure auto replies directly in MailEnable: How to configure auto responder in MailEnable

• Edit the domain's DMARC record, changing its policy to ignore DMARC errors:

  "v=DMARC1; p=none"

  Note: This method won't help with mail relay cases; auto replies may still be sent to spam.