Unable to receive mail from external domain: 5.7.23 SPF validation failed

Ivan Kamnev

Updated March 19, 2025 09:08

Plesk for Linux kb: technical

Applicable to:

Unable to receive an email message from an external domain example.com to a domain hosted in Plesk with the following message in /var/log/maillog file:

CONFIG_TEXT: vps postfix/cleanup[13378]: 05E831D9B: milter-reject: END-OF-MESSAGE from mail.example.com[203.0.113.2]: 5.7.23 SPF validation failed.; from=johndoe@example.com to=janedoe@testdomain.tld
SPF checking mode in Plesk > Tools & Settings > Mail Server Settings is set to Reject mail when SPF does not resolve to "pass".

The SPF check for example.com fails because of an incorrect or nonexistent SPF record on the sender side.

Ask the sender to correct the SPF settings for his domain or apply one of the following workarounds:

Change SPF checking mode

Log in to Plesk.
Go to Tools & Settings > Mail Server Settings.
Change SPF checking mode to less strict, for example, "Only create Received-SPF headers, never block".
Scroll down and press the OK button to apply the changes.

Add the sender domain to the exceptions

Log in to Plesk.
Go to Tools & Settings > Mail Server Settings.
Add example.com to SPF local rules and SPF guess rules fields as described here.

Note: Please keep in mind that if the sender domain doesn't have the TXT SPF record at all then the guess rules will be required as SPF local rules are getting concatenated with the existing SPF record and can only take effect if there is an existing SPF policy present for the sender domain.