Why Are My Klaviyo Emails Going to Spam? A Diagnostic Checklist

By Gurbaj Singh · Reviewed 3 October 2026

You have checked the subject line, removed a few images and sent another test. It still lands in spam. Meanwhile, Klaviyo says people are opening your campaigns, so you are left wondering whether the problem is the template, the domain or the platform.

I would start by separating three things: was the email sent, was it accepted, and where did it land? They need different fixes.

If it was never sent, inspect the flow or campaign recipient status. If it bounced, read the rejection. If it was accepted but landed in spam, investigate authentication, audience quality and sender reputation. Gmail’s Promotions tab is a separate inbox category, not the spam folder.

Here is the diagnostic order I use to make that investigation manageable. Start with the checks below. If you want a guided companion beside your account, the free Klaviyo Spam Troubleshooting Kit includes the decision routes and a completed example.

What a real Klaviyo account shows

On 3 October 2026, I reviewed the last-30-days deliverability report for a DTC brand I work with. The account showed:

Klaviyo labelled the open rate Good, clicks and bounces Excellent, and unsubscribes and complaints Fair. Those labels describe that report’s assessment, not universal targets for every store.

The useful part was the contradiction. If I looked only at opens and clicks, I could stop investigating too early. People were engaging, but other people were also leaving or complaining.

A sunset flow in the same reporting window had a 6.13% open rate, 0.80% click rate and 0.64% unsubscribe rate. Its 0.08% complaint rate represented one complaint. That is a reason to inspect the audience and sending decision, not enough evidence to declare the entire account damaged.

These are anonymised observations, not a before-and-after recovery claim. I have not established inbox placement or the cause of those rates from the dashboard alone.

1. Confirm what is actually happening

Pick one affected message and record its name, send date, recipient provider and observed outcome.

Do not change five settings because a single test inbox looks wrong. A seed test is a useful clue, but your personal inbox has its own interaction history.

For a flow, inspect whether the event happened, the person entered, and the message was waiting, skipped or sent. Klaviyo documents the reasons in its flow-skipping guide. An intentional purchase exit should not be “fixed” by removing the protection.

Record: the exact symptom and the evidence supporting it.

2. Verify authentication on a received message

In Klaviyo, open your account menu, then Settings > Domains. Check the domain used for the affected message type. For a promotional campaign or flow, inspect the marketing sending domain and its activation status.

Then open a received copy of the affected email in Gmail on desktop. Use the message’s three-dot menu and choose Show original. Save the SPF, DKIM and DMARC results and the visible From address. Use the received message you are investigating, not an unrelated email sent from your personal mailbox.

Look for SPF, DKIM and DMARC results. SPF identifies authorised sending infrastructure. DKIM supplies a domain signature. DMARC checks alignment with the visible From domain and applies the domain’s policy.

For bulk senders to personal Gmail accounts, Google’s requirements include SPF, DKIM and DMARC, with the From domain aligned to an authenticated SPF or DKIM domain. See the current Gmail sender requirements.

Use the DNS values generated for your account. Klaviyo’s branded-domain instructions are the reference for the setup you actually have. Copying another brand’s DNS records is not a shortcut.

An authentication pass removes one possible obstacle. It does not prove that subscribers want the email or that a mailbox provider will place it in the inbox.

If something fails: give the saved results and the account-generated DNS records to the person who manages your domain. Verify a fresh message after the repair. Do not replace unrelated records or assume every account uses the same DNS setup.

If everything passes but the email still lands in spam: keep the evidence and continue to the provider and audience checks below. Authentication alone has not identified the cause.

Record: the results from message headers, the From domain and the date checked.

3. Find out whether the problem belongs to one provider

In Klaviyo, open Analytics → Deliverability → Reports. Choose a consistent date window, then compare inbox providers and inspect individual campaigns or flows.

In the account I reviewed, the provider breakdown showed a 0.07% complaint rate for Verizon Media Group and 0.08% for Hotmail / Outlook. Gmail showed 0.00%.

It would be a mistake to conclude that Gmail recipients never complained. Klaviyo explains that Gmail does not supply spam-complaint feedback to ESPs in the same way; use Google Postmaster Tools alongside Klaviyo.

Google recommends keeping its user-reported spam rate below 0.1% and avoiding 0.3% or higher. These are Postmaster Tools measures, not interchangeable thresholds for the complaint-rate column in your Klaviyo report. Google’s sender FAQ explains the distinction and enforcement context.

My next question is whether the change affects every audience at that provider or follows a specific acquisition source, campaign or flow. That gives me a smaller problem to solve.

Record: the affected provider, message group and comparison period. Keep counts beside percentages.

4. Inspect who entered the audience

A list can grow while its usefulness declines. A giveaway, an old migration or a form collecting low-quality signups can create a very different audience from customers who actively requested product updates.

Compare recent subscribers with older subscribers. Then compare signup sources and recent meaningful activity. Preserve the difference between someone who is unengaged and someone who is not eligible to receive marketing.

I would look for:

• Subscribers who received several messages but never showed useful engagement.
• A recently imported group with uncertain permission or missing history.
• A signup source associated with unusually high bounces or complaints.
• Repeat sends to people who have already opted out or been suppressed.

Do not treat a single open as conclusive interest. Apple Mail Privacy Protection can prefetch tracking pixels, which makes some opens ambiguous. Klaviyo provides Apple Privacy Open reporting. Clicks, purchases and recent activity add context, though automated clicks also deserve scrutiny.

The sunset flow in my account review illustrates why audience cleanup needs its own review. Sending a final message to a cold audience is still sending to a cold audience. It is not automatically a safe first step during a reputation problem.

Record: which segment or signup source needs investigation, and why.

5. Reconstruct the customer’s sending calendar

Your campaign calendar is only one part of the customer’s inbox.

Imagine someone joins the welcome series, browses a product, starts checkout and receives a campaign that evening. Each individual message may make sense to its owner. The combined experience can still feel excessive.

Trace a few representative profiles through campaigns and flows. Check the timing, exclusions, purchase exits and Smart Sending decisions. Review the actual recipient record before deciding that a skipped message is lost revenue.

In my lifecycle work, I pay particular attention to what happens after purchase and whether a first-order offer reaches an existing buyer. That same attention helps a deliverability review: a message can be technically deliverable and still be unwelcome.

For provider-specific reputation problems, Klaviyo recommends focusing on engaged audiences and expanding cautiously as performance supports it. Its provider-reputation guide is a useful reference. Choose engagement windows that fit your normal sending frequency rather than copying a segment blindly.

Record: total message pressure on a person, not just sends per campaign.

6. Review the message after checking the audience and infrastructure

Now inspect the email itself.

Does the sender name match the brand the person signed up for? Does the subject line accurately describe the offer? Is the destination link working? Can the reader understand the message without loading images? Is unsubscribing easy?

For marketing mail, check both the visible unsubscribe link and the required one-click mechanism. One does not automatically substitute for the other.

I would also compare the message with the signup promise. Someone who downloaded a technical checklist may not expect daily sales offers immediately afterwards. Better layout cannot repair that mismatch.

Avoid turning this into a hunt for one forbidden word. A plain-text email can still be unwanted; an image-rich email can still be useful.

Record: the specific expectation or usability issue you found.

7. Make a controlled change and review comparable sends

Write a short change log: what changed, which audience it affects and which metric should respond.

If authentication failed, correct that first and verify a new received message. If one audience is causing negative engagement, restrict that audience while investigating. If flow overlap is the issue, test the revised journey before wider use.

Compare similar message types and audiences. A smaller, highly engaged segment may look better partly because its composition changed. Do not present that as proof that the entire domain has recovered.

There is no honest universal “back in the inbox in seven days” promise. The next useful result is evidence: fewer rejections, less negative engagement and healthier performance across the affected provider over repeated sends.

Take the checklist into your account

Get the free Klaviyo Spam Troubleshooting Kit.

The five-page PDF shows where to look, how to interpret the result and which action to take next. It includes a worked review of the anonymised account figures, plus fillable fields for your evidence, next action and verification. Use it beside your account without having to reconstruct the process from this article.

Download my free kit

I work on Klaviyo flow logic, segmentation and reporting. If you want a second pair of eyes on what you find, book a call. Bring the account and the evidence. I will tell you what I would investigate first.