Salesforce Error "550-5.7.26 Unauthenticated email from" and Email Deliverability
550-5.7.26 Unauthenticated email from [DOMAIN] is not accepted due to the domain's DMARC policy The message is unambiguous, you have an issue with the DMARC policy. You can find the message in the email log, in those lines with a "P" in the Mail Event column. But ... can we trust the error message? Well ... let's see. DMARC/DKIM/SPF & NSLOOKUP Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email authentication protocol. It is designed to give email domain owners the ability to protect their domain from unauthorized use, commonly known as email spoofing ... DMARC extends two existing email authentication mechanisms, Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) . It allows the administrative owner of a domain to publish a policy in their DNS records to specify how to check the From: field presented to end users; how the receiver should deal with failures – and provides a reporting mechanism for ac