Plesk mailbox is not receiving email from external domain: Wrong the essential DMARC policy parameters for example.com: Found DMARC record containd a bad token value

Symptoms

• Messages from external domain (example.com) can't be delivered to Plesk hosted domain. Records like below can be found in /var/log/maillog:

plesk dmarc[3935]: 19AC7498C687: Wrong the essential DMARC policy parameters for 'example.com': 'Found DMARC record containd a bad token value'
plesk dmarc[3935]: 19AC7498C687: DMARC: smtpdomain=example.com maildomain=example.com mailfrom=john.doe@example.com stamp=1671104257 ip=203.0.113.2 adkim=unspecified aspf=unspecified p=UNSPECIFIED sp=UNSPECIFIED pct=100 align_dkim=fail align_spf=fail spfres=pass dkimres=pass dmarccheck=DMARC_POLICY_REJECT dmarcstatus=STOP

Cause

DMARC policy misconfiguration on sender domain (example.com).

Resolution

Contact with the administrators of example.com domain and inform them about the issue.

As a workaround, you may exclude a domain from DMARC checks using the steps from How to exclude a domain from DMARC check in Plesk for Linux article.

Additional information

• DKIM, SPF, and DMARC Protection and ARC Support / DMARC

• https://dmarc.org/