Why Email Deliverability Breaks Down


When outbound emails suddenly stop performing, the symptoms are familiar: emails bounce, open rates drop, and replies disappear. Many B2B teams assume the problem is messaging. In reality, email deliverability issues are almost always technical, not creative.

Understanding what’s happening, and how to fix it, is critical before continuing any outreach.

Don’t Use Your Primary Domain for Outreach


One of the biggest mistakes companies make is using their primary business domain for outbound email campaigns. Even warm outreach carries risk. If your domain reputation is damaged, it affects internal communication, customer emails, and overall trust. Best practice is to use alias domains for outbound. These domains redirect to your main site but isolate risk, ensuring your core domain remains protected.

Diagnose Before You Send Another Email


When emails land in spam, the first step is diagnosis. Free spam-testing tools can analyze your inbox setup and explain exactly why messages are being filtered.

These tools focus on three critical authentication protocols:

  • SPF – verifies authorized sending servers
  • DKIM – confirms message integrity
  • DMARC – aligns sender identity and policy

If any of these are misconfigured, inbox providers are far more likely to treat your emails as untrustworthy.

Fix Technical Issues Before Warming Up


Inbox warm-up, reply boosting, or personalization will not work if authentication is broken. If something is technically wrong, emails will continue landing in spam regardless of strategy. Once you identify the issue, fixes are usually straightforward, with extensive documentation and tutorials available online.

Blacklisting: The Hidden Deliverability Killer


Another major cause of spam placement is email blacklisting. There are dozens of blacklist providers that flag domains or IPs due to:

  • High bounce rates
  • Spam complaints
  • Cold email patterns

If you’re blacklisted, outreach should stop immediately. Continuing to send emails only worsens your reputation.

Final Takeaway


Email deliverability isn’t optional infrastructure, it’s the foundation of outbound success. If emails aren’t landing, stop sending, diagnose the issue, and fix the fundamentals before restarting.

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