Few things are more frustrating in email marketing than crafting the perfect campaign… only to discover it landed in spam. The good news? Deliverability issues are almost always fixable once you understand why they happen.

Here’s a clear, practical guide to getting your emails back into inboxes where they belong.

1. Start With the Technical Basics (They Matter More Than Anything Else)

Before you touch your subject lines or rethink your content, check your domain authentication. ISPs (Gmail, Yahoo, Outlook) will distrust your emails if your authentication isn’t set up correctly.

You need three records:

• SPF: Verifies who’s allowed to send email on your domain’s behalf.
• DKIM: Cryptographically signs your emails to prove they weren’t altered in transit.
• DMARC: Tells inbox providers how to handle suspicious mail and gives you visibility into spoofing attempts.

If any of these are missing or misconfigured, your emails are basically guilty until proven innocent – straight to spam they go.

2. Clean Up Your Email List (Engagement Is Everything)

Mailbox providers judge your reputation largely by how people interact with your emails. If you’re sending to a bunch of people who never open anything, providers assume your content isn’t wanted.

Clean your list by:

• Removing subscribers who haven’t opened or clicked in 90 – 180 days
• Getting rid of all hard bounces immediately
• Never using purchased lists
• Considering double opt-in for better long-term health

A smaller, more engaged list almost always performs better—and improves deliverability.

3. Narrow Your Sending to Engaged Subscribers

If your deliverability is in trouble, stop blasting your entire list. Focus only on people who have opened or clicked recently (last 30–90 days).

This “repair phase” warms your sender reputation back up, signaling to inbox providers that your emails arevaluable to recipients.

4. Look Closely at Your Content

Even good content can get flagged if you’re formatting or language triggers spam filters. Watch out for:

• Too many images and not enough text
• Overly promotional phrasing (“FREE! ACT NOW! LIMITED TIME!!!”)
• Excessive buttons or links
• Broken links
• URL shorteners

Aim for clear, friendly, human-sounding copy – just like you’d write to an actual person.

5. Check Your Sending Infrastructure

Your ESP (Mailchimp, SendGrid, Klaviyo, HubSpot, etc.) matters – and so does how you use it. Best practices include:

• Using a dedicated sending domain (e.g., mail.yourbrand.com)
• Slowly warming up new domains or Ips
• Avoiding sudden increases in volume

Think of it like warming up before a workout – you build trust with inboxes little by little.

6. Use Your ESP’s Deliverability Tools

Most email platforms offer insights you should be using, including:

• Deliverability heat maps
• Spam complaint percentages
• Bounce reasons
• Domain – or ISP – specific issues

If you see high complaint rates (>0.1%), that’s a red flag.

7. Make Unsubscribing Easy

This may feel counterintuitive, but:

More unsubscribes = fewer spam complaints = better deliverability.

Never bury your unsubscribe link or make people jump through hoops. If someone doesn’t want your emails, letting them go helps protect your sender reputation.

8. Encourage Subscribers to Whitelist You

A simple ask in your welcome email – “Add us to your contacts to make sure our updates land in your inbox” – can dramatically improve long-term inbox placement. Subscribers who take this step are far less likely to see your emails flagged as spam.

9. Check for Blocklists

If your domain or IP is blocklisted, inbox placement will tank. Use tools like MXToolbox or Spamhaus to check.

If you are listed, don’t panic – fix your sending practices first, then request removal.

10. Keep Your Sending Cadence Consistent

Erratic sending (sending nothing for months and then blasting 5 emails in a week) is a red flag. Inbox providers reward steady, predictable patterns.

Find a cadence you can maintain – weekly, biweekly, or monthly – and stick to it.

Email deliverability isn’t magic – it’s a mix of good technical setup, clean data, and respect for your audience’s attention.

If you fix the technical foundations, clean up your list, focus on engaged recipients, and send high-quality content consistently, your emails will return to the inbox.