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  • Why Microsoft Marks Reported Phishing Emails as Clicked

    When users click the Microsoft Report Phishing button in Outlook, Microsoft Defender automatically scans the links in the reported email. Phishing simulation platforms then register this as a user click -- creating false positives.

    DMARCGuardian Editorial Team · August 2, 2026

  • Deliverability

    What the "Report as Phishing" Button in Outlook Actually Does (And What It Does Not Do)

    When users click Report as Phishing in Outlook, what actually happens on the admin side? This guide explains the data flow, what security teams see, and how to separate a phishing report from an actual phishing click.

    DMARCGuardian Editorial Team · August 2, 2026

  • DKIM

    How to Set Up DKIM for Multiple Domains on One Mail Server (Without Breaking DMARC)

    Running one mail server for multiple domains and seeing DMARC failures? The issue is usually DKIM alignment. Here is how to fix it with per-domain DKIM keys.

    DMARCGuardian Editorial Team · August 2, 2026

  • DMARC

    Why DMARC Fails Even When SPF or DKIM Passes

    SPF checks pass and DKIM verifies, but DMARC still fails. The reason is that DMARC alignment is a separate check from authentication validation, and both must align for DMARC to pass.

    DMARCGuardian Editorial Team · August 1, 2026

  • DMARC

    Why DMARC Fails Even When SPF or DKIM Passes

    SPF checks pass and DKIM verifies, but DMARC still fails. The reason is that DMARC alignment is a separate check from authentication validation, and both must align for DMARC to pass.

    DMARCGuardian Editorial Team · August 1, 2026

  • Deliverability

    How to Migrate from SMTP Basic Auth to OAuth 2.0 for Microsoft 365

    Microsoft deprecated SMTP basic auth for Exchange Online. If your Postfix or Sendmail relay authenticates to Exchange Online, here is a practical migration path to OAuth 2.0, with the failure modes you will actually encounter.

    DMARCGuardian Editorial Team · August 1, 2026

  • DMARC

    DNSSEC Adoption Rates Today: What Breaks and How to Fix It

    DNSSEC deployment is low but growing. Here are the real numbers, common breakage patterns, and how to diagnose failures before they affect your email authentication.

    DMARCGuardian Editorial Team · August 1, 2026

  • DMARC

    What 12,650 DMARC Failures and 179 Passing Messages Actually Mean

    When 12,650 of your emails fail DMARC and only 179 pass, something in your email authentication setup needs attention. Here is what the numbers actually mean and what to do next.

    DMARCGuardian Editorial Team · August 1, 2026

  • Deliverability

    Can Warming Up Your Domain Too Fast Hurt Email Deliverability?

    Sending too much email too quickly from a new domain can trigger spam filters even when SPF, DKIM, and DMARC are all configured correctly. Here is what happens during aggressive warmup and how to ramp up without damaging your sender reputation.

    DMARCGuardian Editorial Team · August 1, 2026

  • Deliverability

    How to Validate Your Domain for Cold Email Sending: SPF, DKIM, and DMARC Explained

    Sending cold email from your own domain? Here is how SPF, DKIM, and DMARC work together to protect your sending reputation and keep your outreach out of the spam folder.

    DMARCGuardian Editorial Team · August 1, 2026

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