The Hidden Costs of Poor Email Deliverability (And How to Fix It)
Why Poor Email Deliverability is Costing You More Than You Realize
Most businesses track open rates, click-throughs, and conversions, but one critical metric often gets overlooked—email deliverability.
If your emails never reach the inbox, everything else does not matter. Poor deliverability leads to:
- Lost revenue from undelivered promotional emails
- Lower customer engagement and brand trust
- Increased marketing costs with lower ROI
- Higher spam complaints and domain blacklisting
So how do you fix it? We spoke with 10 email marketing experts who share their advanced, non-generic solutions to help businesses maximize inbox placement.
1. Reputation Management: The Foundation of High Deliverability
“Your sender reputation is everything. If you ignore it, you’re bleeding potential revenue.”
— Chris Lang, Deliverability Consultant at Email Smart Lab
Chris warns that most businesses focus on content optimization but ignore sender reputation. He recommends:
- Using Google Postmaster Tools to monitor domain health
- Keeping spam complaints under 0.1% to avoid red flags
- Gradual volume increases for new email domains to avoid suspicion
Ignoring these basics means you’re starting every campaign at a disadvantage.
2. Fixing Blocklist Issues Before They Kill Your Campaigns
“You might be on a blacklist and not even know it.”
— Heather Morgan, CEO at SalesFolk
Blacklists can silently ruin deliverability. Heather advises businesses to:
- Use MxToolbox and Spamhaus to check if their domain is blacklisted
- Identify spike points where complaints surged and fix those issues
- Warm up new domains with low-volume, high-engagement emails
“Marketers only check blacklists after noticing a problem. That’s already too late,” Heather adds.
3. Advanced Segmentation to Reduce Spam Complaints
“Stop sending the same email to everyone—it’s a deliverability killer.”
— Dela Quist, Founder of Alchemy Worx
Dela suggests advanced segmentation techniques:
- Engagement-Based Sending – Send frequent emails to active users, but reduce frequency for inactive ones
- Behavioral Segmentation – If a user downloads a whitepaper, send educational follow-ups, not generic promotions
- Sunsetting Policies – Remove subscribers who haven’t engaged in 180 days
This reduces spam complaints, which are the #1 reason emails land in the junk folder.
To further refine outreach and ensure high engagement rates, marketers can integrate Social Media Scheduling Tools to align email marketing efforts with social campaigns. By strategically scheduling posts and promotions across platforms, businesses can create a seamless omnichannel experience that keeps subscribers engaged before, during, and after email campaigns. This holistic approach reduces email fatigue while reinforcing brand messaging, ultimately leading to better email deliverability.
4. How AI Can Predict Deliverability Issues
“AI-driven email monitoring can save your reputation before problems start.”
— Matt West, Deliverability Engineer at Mailgun
Matt explains that AI tools like Validity’s Everest and Mailgun’s Deliverability Monitoring predict inbox placement issues before they happen.
These tools analyze:
- Bounce patterns and spam traps
- ISP filtering trends
- Domain reputation shifts
With AI, marketers can preemptively fix deliverability problems instead of reacting too late.
5. Inbox Placement Testing Before Sending Campaigns
“Testing before sending is the easiest way to prevent costly mistakes.”
— Jen Capstraw, President of Women of Email
Jen warns that marketers assume their emails reach inboxes when many land in spam or promotions.
She suggests using:
- Inbox placement testing tools like GlockApps or Litmus
- Seed lists to test deliverability before launching large campaigns
- Adjusting subject lines and sender names based on test results
A simple test can prevent an entire campaign from flopping.
Scott Allen, Allen Law Firm: Monterey, CA, notes that poor email deliverability isn’t just a marketing issue—it can have legal implications, too:
“Businesses that fail to properly test their email campaigns can inadvertently violate consumer protection laws, leading to legal disputes or regulatory fines. Ensuring emails reach the right recipients and comply with privacy laws is as important as optimizing for conversions.”
6. Why Your Authentication Setup is Probably Wrong
“Without proper authentication, your emails are basically junk mail.”
— Scott Cohen, VP of Deliverability at Braze
Scott sees businesses making fatal errors in authentication, such as:
- No SPF or DKIM records, which makes emails look fake
- Incorrect DMARC policies, leading to blocked messages
- Using shared IPs, which inherit bad reputations
He recommends running domain checks with Google Postmaster and MXToolBox to catch misconfigurations.
Beyond fixing authentication issues, businesses can enhance their email targeting with Leads Navi, a tool that helps identify and deeply understand website visitors. It allows businesses to discover which companies visit their site, access key contact details, and receive recommendations for similar prospects. By integrating Leads Navi, companies can refine their email outreach, ensuring messages are sent to engaged decision-makers rather than cold leads—ultimately improving deliverability and maximizing ROI.
7. IP Warming for High-Volume Senders
“Dumping thousands of emails on a cold IP is the fastest way to get blacklisted.”
— Brian Minick, COO at ZeroBounce
If you’re switching ESPs or using a new sending domain, Brian advises:
- Sending small batches (1,000-5,000 emails/day) initially
- Focusing on highly engaged users first
- Gradually increasing send volume over weeks, not days
“This tells ISPs that you’re a legitimate sender, not a spam bot,” he explains.
8. Hidden Spam Traps That Destroy Reputation
“Spam traps don’t just affect deliverability—they can blacklist your entire domain.”
— Laura Atkins, Co-Founder of Word to the Wise
Spam traps are inactive email addresses used by ISPs to catch spammers. Laura recommends:
- Removing emails that have no engagement in 12 months
- Using double opt-in to prevent fake sign-ups
- Running real-time email validation to block low-quality addresses
9. The Right Email Frequency for Maximum Engagement
“Too many emails can be as bad as too few.”
— Jeanne Jennings, Founder of Email Optimization Shop
Jeanne found that sending daily emails to disengaged users actually lowers inbox placement.
Instead, she suggests:
- High-engagement users: 3-5 emails per week
- Moderate-engagement users: 1-2 emails per week
- Low-engagement users: 1 email per month or re-engagement campaign
This strategy keeps your list healthy without overwhelming subscribers.
10. Avoiding “Graymail” and Deliverability Decay
“If people ignore your emails, ISPs will too.”
— Chad S. White, Head of Research at Oracle CX Marketing
Even if your emails aren’t marked as spam, low engagement hurts deliverability. Chad warns about “graymail”, where:
- Emails land in inboxes but are ignored
- Low engagement tells ISPs to downgrade future sends
- Over time, inbox placement rates drop
The fix? Regularly prune unengaged users and re-optimize content for clicks.
Conclusion: The Cost of Poor Deliverability is Too High to Ignore
Poor email deliverability doesn’t just mean missed messages—it leads to:
- Lost revenue from undelivered promotions
- Wasted ad spend on retargeting users who never saw the first email
- Lower domain reputation, affecting all future campaigns
These 10 expert-backed strategies ensure your emails land where they should—in your customer’s inbox, not the spam folder.