Outlook.com is rejecting some mail from domains with no DMARC record
If your mail to Outlook.com or Hotmail addresses is bouncing with “550 5.7.1 Message rejected: Message lacks SPF/DKIM/DMARC Auth Records,” check whether your domain has a DMARC record. Since November 5, Microsoft’s consumer mail service has been rejecting some messages from domains that don’t have one. Small senders are affected, and so are domains with working SPF and DKIM. Microsoft hasn’t announced or confirmed the change.
