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Avoid common deliverability pitfalls. Learn the top 10 email deliverability mistakes and how to fix them for better inbox placement and engagement.

Introduction

Email deliverability is one of those silent, behind-the-scenes factors that makes or breaks your email marketing. You might have amazing content, visuals, and offers, but if your emails land in spam or never arrive, all that work is wasted.

In this guide, you’ll discover 10 common email deliverability mistakes, why each one matters, and how to fix them - to improve deliverability, inbox placement, and your overall email performance.

1. No or Incorrect Email Authentication (SPF / DKIM / DMARC)

Why this matters: Mail providers check if your domain is authorized to send emails. Without proper SPF, DKIM, and DMARC, your messages may be marked as spam or rejected. 

Fix:

> Publish SPF records to authorize your sending IPs

> Enable DKIM signing

> Set up DMARC policy with reporting (p=quarantine or reject)

> Use testing tools (e.g. MXToolbox, DMARC analyzers) to verify setup

2. Using Free or Inconsistent “From” Addresses

Why this matters: Using a @gmail.com or @hotmail.com address hurts credibility. Inconsistent “From” names confuse your audience.

Fix:

> Always send from a branded domain (e.g. [email protected])

> Use a consistent “From name”

> Avoid generic “no-reply” unless necessary

3. Buying Lists or Using Scraped Addresses

Why this matters: These addresses often bounce, are invalid, or uninterested - causing high bounce/complaint rates and damaging your sender reputation.

Fix:

> Build lists via permission-based opt-ins

> Use double opt-in to confirm address validity

> Never send to unvetted third-party lists

4. Neglecting List Hygiene & Inactive Subscribers

Why this matters: Sending to dead or disengaged addresses drags down metrics and hurts sender score.

Fix:

> Regularly remove hard bounces

> Run re-engagement campaigns for dormant users

> Archive or unsubscribe those who don’t respond

5. Sudden Volume Spikes / Over-Sending

Why this matters: ISPs flag sudden increases in sending volume or overly frequent sends as suspicious.

Fix:

> Warm up new IPs or domains gradually

> Maintain a consistent sending cadence

> Segment new or low-engaged subscribers and limit frequency

6. Spammy Language, Poor Formatting & Trigger Words

Why this matters: Filters scan for promotional overuse (“FREE,” “BUY NOW!!”), broken code, suspicious links. 

Fix:

> Avoid overused “spam words”

> Keep a balance of text and images

> Use clean, valid HTML

> Test your emails through spam-check tools

7. Using URL Shorteners or Redirect Chains

Why this matters: Shortened or redirected links are often flagged as suspicious by filters.

Fix:

> Use direct links to your own domain

> Minimize redirect chains

> If you use a shortener, use a custom, reputable one under your domain

8. High Spam Complaints & Poor Unsubscribe Handling

Why this matters: Spam complaints and unsubscribes directly affect your reputation and deliverability.

Fix:

> Always include a visible “unsubscribe” link

> Use a preference center (frequency, topics)

> Honor unsubscribes instantly

> Monitor complaint rate thresholds (e.g. < 0.5%)

9. Ignoring Engagement Metrics & ISP Feedback

Why this matters: ISPs use opens, clicks, and complaint feedback as signals for future inbox placement.

Fix:

> Monitor opens, clicks, bounces, complaints

> Use ISP feedback loops (e.g. Gmail, Yahoo)

> Segment users by engagement and adapt content or frequency

10. Not Monitoring Blacklists & Reputation

Why this matters: If your sending IP or domain is blacklisted, emails may be blocked outright or go to spam.

Fix:

> Regularly check blacklists (Spamhaus, etc.)

> Use reputation monitoring tools

> If blacklisted, follow removal process (clean list, request delisting)

> Maintain good sending behavior

Conclusion & Action Plan

Deliverability underpins the success of every email marketing campaign. No matter how compelling your content is, it won’t matter if your messages never reach the inbox.

What to do next:

> Audit your setup: SPF, DKIM, DMARC

> Clean your list - remove invalid and inactive addresses

> Ramp sending carefully; maintain consistency

> Avoid spammy content; use clean HTML and reputational links

> Monitor metrics, reputation, and blacklist status