What is it?
This mail DNS finding means the domain does not publish a DMARC TXT record at _dmarc.<domain>. DMARC defines how receivers should evaluate mail that uses your visible From: domain.
Why does it matter?
Without DMARC, receivers do not have a domain-level policy for aligned SPF and DKIM results. That makes spoofing harder to control and prevents you from receiving aggregate reports that show who is sending mail for your domain.
How to fix it?
Publish a DMARC TXT record and configure a mailbox or reporting endpoint for aggregate reports.
_dmarc.example.com. 3600 IN TXT "v=DMARC1; p=none; rua=mailto:dmarc@example.com"Start with p=none while you inventory legitimate senders. After SPF or DKIM alignment is reliable, move toward p=quarantine or p=reject.