In CRM marketing, everyone obsesses over segmentation, personalisation, or the perfect subject line, but what if none of it lands because your emails never make it to the inbox?

That’s the painful reality of poor domain health. It’s invisible at first, until one day, your open rates plummet, your ESP gives you warnings, and your brand reputation quietly deteriorates.

It doesn’t matter how brilliant your segmentation, content, or “Hi {First Name}” trickery is — if your emails don’t land, none of it matters.

And the worst part? You won’t even notice. Until it’s too late. This article breaks down real problems I’ve encountered behind the scenes — and how to avoid setting your CRM on fire.

Case Study Context

In one project I led, the client’s goal was simple on paper: increase email deliverability and improve overall domain health.

But the situation was far from ideal:

• No verification tools were in place.

• Cold leads were blasted with generic emails.

• There was no limit on outreach frequency.

The result? Spam folder galore.

Our target: a 99% deliverability rate.
Our outcome: +13% MoM client increase from improved deliverability alone.

Here’s how we turned it around.

Problem 1: No Email Verification Process

Sending emails without verification is like handing out flyers with the wrong address. You're burning sender reputation with every bounce.

What we found:
No email validation for outbound campaigns, and no opt-in checks on inbound leads. It was a free-for-all.

What we did:
For outbound:

• Integrated Emailble for cold email validation.

• Cross-checked leads with trusted providers like Honch.

For inbound:

• Built an opt-in check automation.

• Set up a marketing contact assignment flow in CRM to manage new leads based on source and behaviour.

Problem 2: Cold Leads, Mass Blasts, and Database Decay

Nothing screams "bad CRM hygiene" like uploading scraped lists and spamming everyone. And yet… it’s more common than you'd think.

What we found:
The same database was used for cold outreach and lifecycle communications. No segmentation, no access control, and zero regard for engagement signals.

Our fix involved three key phases:

1. Preparation

• Used a separate domain for cold outreach.

• Set up a dedicated drip tool (vs. standard CRM ESP).

• Restricted CRM access — only key admins could upload lists.

• Added source-based segmentation workflows and tags.

2. Prevention

• Built segments based on engagement recency (3/6/9/12 months).

• Set monthly calendar reminders for data cleaning.

• Excluded all cold or inactive contacts from lifecycle flows.

3. Monitoring & Damage Control

• Ran domain health audits with Google Toolbox, Postmaster Tools, and GlockApps.

• Monitored flagged addresses and bounce reports via our ESP’s internal tools (like “Email Health” in Hubspot).

Problem 3: The 5x Per Week Blast Mentality

When teams think "more emails = more sales", deliverability starts nosediving. Fast.

What we found:
One team scheduled five mass sends per week — to the entire database. Zero personalisation, zero pacing.

Our solution:

Preparation (Outbound):

• Segmented outreach lists and implemented progressive warm-up.

• Scheduled regular lead pool refreshes (to avoid repetition and fatigue).

Preparation (Inbound):

• Defined communication limits — max # of sends per contact/week.

• Instituted bounce and unsubscribe tracking to detect friction.

Damage Control:

• Built a dedicated “Engaged Contacts” list for future sends.

• Flagged low-performing subject lines and high-bounce segments.

• Adjusted content strategy based on Email Health reports.

It’s easy to treat deliverability like a passive metric — something to monitor, not manage. But domain health isn’t just technical hygiene; it’s foundational. It decides if your strategy sees daylight… or spam folders.

Want the full Domain Health Checklist we used during this project? Join our CRM Collective Slack community to access exclusive content, templates, and bonus materials shared by fellow marketers.

Additional resources to get deeper into the tech (and avoid deliverability drama): Click on the links below.

• SPF, DKIM, and DMARC Setup Guides 

• Best Email Verification Tools 

• Google’s SPF + Google DKIM 

• Spam Trigger Words to Avoid 

• Best Email Verification Tools 

• Spam Trigger Words 

• Gmail Spam Avoidance Tips