Why Are My Klaviyo Emails Going to Spam?

Klaviyo emails usually end up in spam when inbox providers (Gmail, Yahoo, or Outlook) don’t trust the sender enough. That could be because your authentication isn’t set up right, engagement has dropped, the content looks spammy, or you’re sending too many dead addresses.

And the fix depends on what’s actually happening. Sometimes it’s a quick DNS fix. Other times, you need to clean up the list or slow down your sending.

So let’s look at what’s happening first. We’ll start with what inbox providers are actually looking at, then check the important stuff in Klaviyo, and finally look at a real example to see how you’d work out what to fix first.

Key takeaways

Confirm the symptom first: emails landing in spam, going to the Promotions tab, or getting fewer opens.
Expect more than one possible cause: spam placement is rarely caused by just one thing.
Check authentication and sender reputation first.
Check engagement and list quality too: both can affect where your emails land.
Check the evidence to figure out what to fix first.

Why Klaviyo emails end up in spam

Inbox providers look at three main signals when deciding where your email goes.

1 Who you are Your authentication and sending history.

2 How people respond Opens, clicks, replies, and spam complaints.

3 What is in the email Links, images, copy, all that stuff.

Here's the thing: those three often show up looking the same, but once you pull them apart, they behave very differently.

Spam folder, Promotions tab, or weak opens

Let’s first make sure we’re talking about the same problem, because these three get mixed up all the time...

1 Spam / junk The provider decided not to put the email in the inbox. That’s the problem we’re talking about here. At higher volume, authentication or unsubscribe issues can also stop the send before it even gets that far.

2 Promotions tab The email made it to the inbox. It just landed in Promotions instead of Primary. That might hurt clicks, but it doesn’t mean you’re going to spam.

3 Soft engagement Fewer opens don’t necessarily mean bad placement. Apple Mail Privacy Protection can scramble open rates on iPhone, so I wouldn’t use opens alone to decide this is spam.

Figure it out which one you actually have before you start fixing.

Do this in 10 minutes

1
Ask 5–10 recent subscribers where the latest campaign landed: Primary, Promotions, or Spam.
2
Open Google Postmaster Tools for your sending domain and check spam rate plus Compliance Status - the checklist Gmail uses to show whether you're meeting its sender requirements.
3
Send the same campaign to seed addresses you control on Gmail, Yahoo, and Outlook.
4
Check your bounce rate and spam complaint rate in Klaviyo for the last 30 days.

If subscribers see the email in Promotions and Postmaster looks stable, start by looking at tab placement and content.

If your seed tests land in junk, your Postmaster spam rate is rising, or Compliance Status shows a failed check, work through the possible causes below.

The 5 causes that pull Klaviyo mail into spam

tap a cause to read more...

Authentication problems (SPF, DKIM, DMARC)

If these records are missing, broken, or outdated after a domain change, providers have a harder time trusting you.

If these records are missing, broken, or outdated after a domain change, inbox providers may have a harder time trusting that your emails really come from you. Think of it like showing up at the airport with an expired ID.

In Klaviyo this usually means a branded sending domain you control, such as send.yourbrand.com. Shared sending is fine when you’re starting out. As volume grows, a branded domain gives you more control over reputation.

What to check...

SPF: set up correctly and aligned with your sending domain.
DKIM: Klaviyo’s DKIM records are on that sending domain.
DMARC: the From domain has a DMARC record, at least p=none.
Alignment: the domain people see in From matches the domain authenticated through SPF or DKIM.

Having the records in place isn’t enough. They also need to be aligned. Re-check after a DNS update, website migration, or agency handoff. Then send yourself a test, open the original headers, and confirm SPF, DKIM, and DMARC all passed. Don’t stop at “Verified” in Klaviyo.

Sender reputation

Gmail, Yahoo, and Outlook pay attention to how people respond to your emails.

If more people start marking your emails as spam, ignoring them, or unsubscribing, your sender reputation can take a hit over time. The same thing can happen when sending volume suddenly jumps.

Say you normally send three campaigns a week, then start sending every day. The increase itself isn’t necessarily the problem. If people don’t respond well to the extra mail, providers can start treating you differently.

What to check... over the last 30 days in Klaviyo: spam complaints, bounce rate, unsubscribe rate, click rate, and sending volume. Then check Google Postmaster Tools for that same period.

Focus less on one bad day and more on the trend. Are complaints slowly going up? Are clicks going down? When someone says “our emails are going to spam,” the problem often started weeks earlier.

List quality

Your list can slowly get less healthy without you noticing.

Your list can slowly get less healthy without you noticing. People stop opening, some addresses become invalid, and giveaway signups sit next to buyers who still want the emails. When you send a campaign, everyone gets treated pretty much the same.

What to check... build a segment of people who haven’t opened or clicked in the last 90–180 days, then see how much of a recent campaign went to that group.

You don’t have to delete them. Suppress them from regular campaigns first. You can try a re-engagement send later. Inactive subscribers shouldn’t be treated the same as people who are still engaging.

Gmail and Yahoo bulk-sender rules

These extra rules kick in once you’re sending around 5,000 or more emails a day to Gmail.

These extra rules kick in around 5,000 or more emails a day to Gmail. Yahoo has a similar bar in its Sender Hub.

Check three things: SPF, DKIM, and DMARC aligned with the sending / From domain. One-click unsubscribe on campaigns and flows. Complaint rate under the published threshold.

Klaviyo already adds the List-Unsubscribe and List-Unsubscribe-Post headers on marketing mail. Still test it: send yourself a real email, open Gmail, click Show original, and confirm both headers are there. Transactional mail doesn’t need the header.

If auth or the unsubscribe header fails at this volume, Gmail may reject the send. That can look like a normal bounce, so check delivery errors too, not just the Spam folder.

Content and engagement patterns

Start with what changed before the drop: template, promo mix, or send frequency.

Start with what changed before the drop. Did you switch templates, start sending more promos, or go from three emails a week to every day? Any of those can change how people respond, and filters pick that up too.

Compare your last 5 campaigns with the 5 before the drop. Look at send frequency, template, offer density, subject lines, and click rate. I’d pay more attention to clicks than opens.

A few things may have changed at once. If the subject line changed along with the template or send frequency, look at all of them together. Changing the subject line alone won’t fix the rest.

What to check first in Klaviyo

If you’re trying to figure out what’s actually going on, I’d check things in roughly this order.

Check these in order...

0 of 7 checked

Start with your sending domain. Make sure your branded sending domain is verified in Klaviyo, then send yourself an email. You want to see SPF, DKIM, and DMARC passing and aligned on an actual email.
Check Postmaster. Make sure it’s connected to the same sending domain, and have a look at your spam rate and Compliance Status.
Compare engagement. Look at your open and click rates for the last 30 days and compare them with the previous 30 days. If your opens look strange or inconsistent, I’d put more weight on clicks.
Check bounces and complaints. Look at your bounce rate and spam complaint rate over the same period.
Look at your audience. Check who you’re sending to, especially how much of your list has been inactive for the past 90–180 days.
Review recent changes. Think back to anything that changed around the time the problem started, such as a new template, subject-line changes, a launch, more promotional emails, or a sudden increase in send frequency.
Run the bulk-sender checks. If you’re sending around 5,000+ emails a day to Gmail, go through the bulk-sender requirements too. For example, check the one-click unsubscribe headers on an actual marketing email.

At this point, you should have a much better idea of what’s actually driving the problem, whether it’s authentication, sender reputation, list quality, bulk-sender requirements, or something in the content itself.

If you want to go deeper, see how to audit Klaviyo in 2026. And if your opens look fine but sales or orders are the problem, read why your Klaviyo welcome flow isn’t converting.

How a structured diagnosis confirms the root causes

The checks above help narrow things down. Then you still need to figure out which causes are confirmed in this account, and which one you should deal with first.

Email DDx answers that in a short sequence...

Email DDx The Email DDx sequence

Gather the context and symptoms What changed, when the problem started, and what you’re seeing in Klaviyo, Postmaster, and the inbox.
List the possible causes Go through the causes that could explain what’s happening with your email placement.
Gather evidence and test Compare what happened with your Klaviyo data, authentication reports, and seed tests to see which causes hold up.
Treat the confirmed causes Fix them in order, then keep an eye on things for the next 2–4 weeks.

Let me walk you through a real example so you can see how this works in practice. The case below is that same pass, laid out step by step.

Case file Skincare brand on Klaviyo

Worked Example: A Skincare Brand Whose Emails Started Landing in Spam

A skincare brand using Klaviyo saw its open rates drop over six weeks. More subscribers were also reporting that emails were landing in spam or Promotions. The team changed the copy, but placement stayed poor.

Here’s what we already knew...

Email revenue: Email was bringing in about 30% of the brand’s monthly revenue.
Send frequency: They normally sent three campaigns a week, but switched to daily sends for two weeks during a launch.
New template: Opens started dropping around the same time they introduced a new template.
List growth: The list had grown quickly through giveaway campaigns.

The two main symptoms

Email revenue dropped.
More emails were landing in spam.

Possible causes

From there, we looked at the possible causes: authentication failure, sender reputation drop, spam complaints from unengaged subscribers, list quality decline, content or technical issues in the template, subject lines or offer wording, and low engagement signals.

Then we started checking the evidence...

Evidence found	Authentication	Template / HTML	Reputation / volume	List quality
SPF error after a domain move	Strong confirm	Neutral	Refute	Neutral
New template with rendering issues and no plain-text version	Neutral	Possible	Neutral	Neutral
Sending jumped from 3x a week to daily for 2 weeks	Neutral	Neutral	Strong confirm	Neutral
40% of the list inactive for 6+ months	Neutral	Neutral	Weak confirm	Strong confirm
Complaint rate rose during the daily-send period	Neutral	Neutral	Strong confirm	Strong confirm
Gmail seed test landed in spam	Weak confirm	Possible	Weak confirm	Neutral

Evidence from one Klaviyo account mapped against possible spam causes.

A seed test showed where the email landed, while the SPF error needed a DNS check. We kept the new template on the list because Gmail started showing spam placement around the same time it was rebuilt. The missing plain-text version was a weaker signal on its own, so we treated it as part of the template issue rather than a separate cause.

What the tests showed

SPF: The error was confirmed and fixed.
Template: The new template landed in Gmail spam but reached the Outlook inbox.
Complaints: Complaint rates went up during daily sending and stayed high after the launch.
List health: The list had grown 35% over eight months, mostly through giveaways, while inactive profiles were still receiving regular emails.

Other factors: Promotional wording, the sender name, and the subject line were ruled out because the evidence didn’t point to them.

Treatment order

The useful part of this example is the order. Authentication first. Then the template Gmail was rejecting. Then the list and the cadence that were feeding complaints.

Fix the SPF record in DNS.

Rebuild the template with clean HTML and a plain-text version.

Suppress profiles with no opens or clicks for 6+ months.

Return to a steady 3x-per-week cadence.

Run a short re-engagement send for the quieter part of the list, then keep the remaining inactive profiles suppressed.

30 days later...

Open rate 14% → 27%
Spam complaints 0.08% → 0.01%
Gmail spam Close to zero
Email revenue $6,000 → $15,500 / mo
Re-engagement Brought back 8% of inactive subscribers. The rest stayed suppressed.

The starting complaint rate was already below Gmail’s 0.3% threshold, so the bigger signal was the rise during daily sending, alongside the other confirmed causes. Placement can keep changing for 2–4 weeks after treatment, so we treated this as a checkpoint rather than the final result.

Keep your sending schedule steady while you watch complaints and inbox placement. A sudden catch-up blast can undo the progress you’ve just made.

Frequently asked questions

Why do my Klaviyo emails suddenly start going to spam?

A sudden drop usually happens when something changes while there’s already a problem in the background. Maybe you moved domains and broke SPF or DKIM, suddenly increased your sending volume, or rebuilt a template with technical issues. And if you already have a lot of subscribers who haven’t clicked anything in months, that can make things worse. Sometimes, one change is enough to send your emails to spam.

How can I tell if the emails are in spam, or if opens are just down?

First, ask subscribers where the email actually landed. Run a seed test across Gmail, Yahoo, and Outlook, then check Postmaster spam rate and Compliance Status alongside your Klaviyo complaint data.

If those all look fine and the only thing that’s changed is your open rate, check Promotions placement and Mail Privacy Protection before you call it a deliverability problem. Open rates can be misleading, especially with Apple’s privacy changes.

How can I stop Klaviyo emails from going to spam?

Once you know what’s causing the problem, start fixing those things one by one. First, make sure your sending domain is properly authenticated and aligned. Then look at complaints, bounces, and clicks from the last 30 days, and check how many people on each send are basically inactive.

From there, look at how often you’re sending, your template, and your subject lines. See if the data points to any of them. If you’re a bulk sender, make sure one-click unsubscribe is working too. Then keep your new sending schedule steady for 2–4 weeks. Your reputation won’t bounce back overnight.

Can sending too often or emailing old subscribers push Klaviyo mail into spam?

Yeah, absolutely. And honestly, these things can make each other worse. Sending every day can lead to more complaints, while a big group of people who haven’t clicked in six months can drag down engagement too. So take them out of your regular sends, give the people who still seem interested a chance to come back, and then get back to sending to them regularly.

What to do next

You now have the five causes that usually pull Klaviyo mail into spam, the 10-minute checks that separate spam from Promotions from opens that look low, and a way to put the confirmed causes in order.

Start with the 10-minute pass: ask a few subscribers where the last campaign landed, open Postmaster, run one seed test, and read 30 days of bounces and complaints in Klaviyo. Treat the confirmed cause first. Hold the new setup for 2–4 weeks and watch placement again.

Written by

Russell Cargill Email Specialist · 10+ years in email

LinkedIn YouTube

Founder of InboxConnect and EmailDDx. Specializes in diagnosing and fixing email marketing for Klaviyo and Shopify brands. Previously worked with Beehiiv.

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