Fix "550 5.7.1 (DMARC, Outlook)": Outlook rejected the message for failing DMARC

Bouncing with 550 5.7.1 (DMARC, Outlook)? It means Outlook rejected the message for failing DMARC.

How to fix it

Align SPF or DKIM with your From domain and publish DMARC.

Prevent it

• Authenticate with SPF, DKIM and DMARC.
• Send from a dedicated IP.
• Keep bounce and complaint rates low.

How Rainmail helps

Rainmail sends from your own domain on a dedicated, isolated IP with SPF, DKIM, DMARC, reverse-DNS and managed warm-up handled for you, plus a REST API and an AI watching deliverability — and it welcomes senders SES, SendGrid and Mailchimp reject, from $8. Run the free checker or see plans.