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  • DMARC

    Why Most of Your Email Fails DMARC Alignment Even When SPF or DKIM Appears to Pass

    When your DMARC report shows thousands of failures but only a handful of messages pass alignment, the problem is almost always alignment, not authentication. Here is why and how to fix it.

    DMARCGuardian Editorial Team · July 25, 2026

  • Deliverability

    Device-Code Phishing: How Attackers Bypass MFA and Passkeys

    Device-code phishing bypasses MFA by walking victims through the real Microsoft login page. Here is how the attack works and what controls stop it.

    DMARCGuardian Editorial Team · July 25, 2026

  • SPF

    How to Add Multiple Email Services to Your SPF Record Without Breaking It

    Each third-party email service you add to your SPF record chains more DNS lookups. Go over 10 and SPF breaks silently, failing all your mail. Here is how to diagnose it, fix it, and verify the fix.

    DMARCGuardian Editorial Team · July 25, 2026

  • Deliverability

    What to Do Before the OWA Light Retirement Deadline in Exchange Server

    Microsoft is disabling OWA Light in Exchange Server. Here is how to identify affected users, migrate them to full OWA, and avoid losing web mail access when the retirement date arrives.

    DMARCGuardian Editorial Team · July 25, 2026

  • Why BIMI Records Fail and How to Get Them Working

    BIMI validation fails without clear error messages. This guide explains the three most common failure points -- the TXT record, the SVG logo, and the CA certificate -- and how to fix each one.

    DMARCGuardian Editorial Team · July 24, 2026

  • DMARC

    What DMARC Failure Reports Tell You and How to Act on Them

    DMARC aggregate reports reveal every source sending mail on behalf of your domain. Here is what the report fields actually mean and which failures require action.

    DMARCGuardian Editorial Team · July 24, 2026

  • Deliverability

    Why Email DLP Blocks Attachments But Lets Anonymous OneDrive Share Links Through

    Email DLP that catches sensitive file attachments often misses anonymous OneDrive share links to the same files. Here is why this gap exists, how to find it in your logs, and what monitoring closes it.

    DMARCGuardian Editorial Team · July 24, 2026

  • DMARC

    DMARCbis: What the RFC Update Means and When to Adopt

    DMARCbis is the first meaningful update to the DMARC RFC in years. Here is what actually changes, what the new np tag does, and when you should start preparing.

    DMARCGuardian Editorial Team · July 24, 2026

  • DMARC

    How DMARC Aggregate Reports Catch Sending Problems Before They Become Outages

    DMARC aggregate reports reveal which subdomains are sending mail without SPF, which third-party services are misconfigured, and which IPs are failing authentication. Learn what to look for and why only automated monitoring catches these problems before they take down your email.

    DMARCGuardian Editorial Team · July 24, 2026

  • DMARC

    How to Move Your DMARC Policy from p=none to p=reject Without Breaking Email

    A practical three-phase guide to migrating from DMARC p=none to p=reject without disrupting legitimate email. Covers aggregate report analysis, common breakage patterns, and how to move with confidence.

    DMARCGuardian Editorial Team · July 24, 2026

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