General
What DMARC means
DMARC (Domain-based Message Authentication, Reporting, and Conformance) works by leveraging SPF and DKIM to authenticate incoming email messages. For an email to pass DMARC, it must pass either SPF or DKIM (or both), and the domain used in the From header must match the authenticated domain. Learn more: https://en.wikipedia.org/wiki/DMARC