Why Your Emails Land in Spam (and How to Fix It)

Why This Keeps Happening

Deliverability is your sender reputation with Google, Yahoo, and Outlook. They score you. They do not sit and read your email deciding it looks spammy.

Every sending domain has a reputation in their eyes. Good reputation lands you in the primary tab, average reputation lands you in promotions, and bad reputation drops you in spam, where emails go to die.

Reputation and engagement drive that score far more than the words in your subject line. Last year we helped our clients do a combined $20 million from email and SMS, and almost none of that comes from senders sitting in the spam folder.

Gmail watches how people treat your mail. Send to a wide audience and only 10% open, and providers assume your mail is not valuable, so your reputation drops and you slide into promotions or spam.

Flip that around. When 50% open, plenty click, and a few even reply, your reputation climbs and you hit the primary inbox far more often.

That is the feedback loop. High engagement means better placement, which means more people see and open your mail, which means better placement again. Low engagement is the same loop in reverse, a downward spiral that quietly loses brands a lot of money.

That one signal outweighs almost everything else.

Prefer to watch? Here is the fix on video.

Confirm Where You Actually Land

Opens and clicks give you a strong first read on deliverability. Under 30% opens is a warning sign.

To go one step further, run a seed test through GMass, GlockApps, MailTester, or MailGenius. These tools simulate real inboxes and show you exactly where your mail lands across Gmail, Yahoo, and Outlook.

This matters because so many brands are going to spam and do not even know it. They think their numbers are fine when they are quietly bleeding revenue. Test it, or get an expert to test it for you, so you are not guessing.

The Real Causes

Content matters, but it is rarely the root problem.

These are the causes that actually move you to the spam folder, roughly in order of impact.

• A shared sending domain. Klaviyo starts you on a shared IP with a pile of other brands. When newbies with poor deliverability send on that same IP, your reputation takes the hit. This is one of the worst mistakes an ecommerce brand can make.
• Broken authentication. Missing or misconfigured SPF, DKIM, or DMARC tells providers you might be a spoofer.
• Sending to your whole list. Blasting every contact, no segmentation, is by far the most common issue and it nukes your deliverability.
• Emailing unengaged contacts. People who have not opened in 90+ days drag your reputation down with every send.
• Sudden volume spikes. Jumping from 5,000 to 50,000 sends overnight looks like a compromised account.
• Cold or purchased lists. Imported contacts who never opted in produce complaints and hit spam traps.
• High complaint rates. Once you cross roughly 0.1% marking you as spam, providers act fast.
• Spammy formatting. All-caps subject lines, "FREE!!!", and single giant image emails with no text.
• Broken or shortened links. Dead URLs and public link shorteners are classic spam signals.

The Fix Path

Work these in order.

Skipping ahead to content tweaks while your list is full of dead contacts wastes your time.

A staged rebuild is the same discipline as a new domain warmup.

Build engaged segments the simple way: person can receive email marketing and has opened or clicked in the last 15, 30, 60, 90, or 180 days. Send the bulk of your campaigns to the tightest window that keeps opens above 40%, and only widen once that number holds. Reserve maybe one full-list send a month to re-engage the rest.

If you are recovering a burned reputation, follow the full deliverability and domain warmup guide step by step.

Match the Symptom to the Cause

Skip the guessing. Find your symptom, then jump straight to the fix.

Text-to-Image Balance

File size is the part most brands miss.

Heavy HTML emails, the ones stuffed with colored text, nav bars, dynamic sections, and HTML buttons, balloon your file size. Sending one is like mailing a hundred-page document to your neighbor. It loads slowly and it clips in Gmail. Aim to keep every email under 90 to 102 kilobytes.

Here is what we actually do. We send image-only emails with a little HTML text in the footer. Images do not add much to file size, so we skip the colored text and nav bars and render those elements as a single image instead. That is how we send our clients' mail at 70-plus deliverability scores while making them millions a month.

Three rules make image emails safe: always add alt text, always compress your images, and lean on plain-text emails when your deliverability is already poor. Plain text means minimal color and formatting, tiny file size, and a real lift in placement.

Providers cannot read an image, so live text still matters. An email that is one big graphic with nothing else gives them nothing to score except your reputation, and it breaks when images are blocked by default. The fix is not zero images, it is image plus real text plus alt text.

Benchmarks to Watch

Check these every send. Drifting into the "Needs Work" column is your early warning.

Catch it here and you fix a dip before it becomes a block.

Better segmentation lifts every number in that table.

Sending the right message to the right people is the cleanest way to raise engagement. Our email segmentation strategy guide shows how to build the segments that keep you in the inbox.

Common Mistakes

1. Emailing your whole list every time. Segment by engagement so dead contacts stop dragging your score down.
2. Ignoring authentication. Set up SPF, DKIM, and DMARC once and confirm all three pass before sending.
3. Importing a list and blasting it. Warm up new contacts slowly and never send to bought data.
4. Chasing content while the list is stale. Prune non-openers before you rewrite a single subject line.
5. No sunset policy. Automatically drop contacts who have not engaged in 120 days so they never rot on your list.
6. Hiding the unsubscribe link. Getting marked as spam is far worse than an unsubscribe. Make unsubscribing easy so unhappy contacts leave quietly instead of hitting the spam button.
7. Running giveaways to grow the list. Giveaways and free-stuff promos pull low-quality subscribers who never buy. They inflate your list size and drag down engagement. To keep quality high, require a real email to claim a discount and use a CAPTCHA, email verification, or double opt-in on your signup forms.
8. Finding out from revenue. Watch Postmaster Tools weekly so you catch a dip before it becomes a full block.

Monitoring Checklist

• SPF, DKIM, and DMARC all pass
• Google Postmaster Tools connected and checked weekly
• Spam complaint rate under 0.1%
• Open rate tracked on every send
• Bounce rate under 1%
• Sunset rule live for 120-day non-openers
• Blacklist status checked monthly

Get Expert Help

Deliverability problems quietly drain revenue long before you notice them.

Our team diagnoses why your mail lands in spam and rebuilds your sender reputation as part of our retention work.

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