Blogs
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DMARC
How to Set Up SPF, DKIM, and DMARC for Multiple Domains on One Mail Server
A practical guide to configuring SPF, DKIM, and DMARC across multiple domains on a single mail server. Covers SPF lookup limits, per-domain DKIM signing, DMARC alignment, and the configuration mistakes that break legitimate mail.
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Deliverability
AOL Bouncebacks to Office 365: Why the NDR Is Useless and What to Do Instead
When your Office 365 email bounces to an AOL recipient, the NDR rarely tells you why. Here is how to find the real reason and fix it.
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DMARC
RFC 9989: What Changes When DMARC Stops Using the Public Suffix List
RFC 9989 replaced the static Public Suffix List with a DNS-based method for finding organizational domains. Here is what domain owners, cloud email users, and subdomain operators need to know.
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DKIM
Why DKIM Fails After a DNS Migration and How to Prevent It
DNS migrations corrupt multi-string DKIM TXT records, causing permerror failures. Here is how to catch it before it breaks email delivery and how to prevent it during your next DNS change.
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DMARC
Why Your Brevo Emails Fail SPF or DKIM Alignment (And How to Fix It)
Emails from Brevo going to spam because of SPF or DKIM alignment failures? The fix is in how you configure Brevo's DNS settings, not in Brevo itself.
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DMARC
RFC 9989 and DMARC: What Changed and What Multi-Domain Organizations Need to Do
RFC 9989 modernized DMARC by removing the Public Suffix List dependency. This guide explains what changed, why it matters for multi-domain organizations, and how to update your DMARC setup.
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Deliverability
What Actually Drives Email Deliverability in 2026: Reputation vs. Authentication
Authentication passing does not guarantee inbox delivery. This guide covers the factors that actually determine email deliverability in 2026, including sender reputation signals, authentication results, and what DMARC reports reveal about why legitimate email lands in spam.
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Deliverability
Why Microsoft Outlook Marks Reported Phishing Emails as Clicked
Microsoft Defender auto-visits links in reported emails, which makes phishing simulation platforms log a false click. Here is how to configure reporting to prevent this.
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DMARC
How to Stop Exchange Hybrid NDRs from Leaking Internal Group Names to External Senders
In Exchange hybrid environments, bounced messages to restricted groups can expose internal distribution group names to external senders. Here is how to prevent that disclosure.
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DMARC
How to Move DMARC from p=none to p=reject Without Breaking Your Email
Step-by-step guide to tightening DMARC from monitor mode (p=none) to reject (p=reject), including aggregate report analysis, common failure patterns, and a safe migration sequence using pct.