Klaviyo Deliverability: The Complete Diagnostic Guide

# Klaviyo Deliverability: The Complete Diagnostic Guide

Your Klaviyo emails used to land fine. Now opens are sliding, a few customers say they found you in spam, and nobody can say for sure what changed.

That's a deliverability problem, or at least it looks like one. The good news is that it can almost always be traced to a cause you can find and fix.

This guide walks through the symptoms one at a time. Each section explains what the symptom usually means, what to check first, and where to read more.

Why guessing makes deliverability worse

When mail starts landing in spam, the natural instinct is to change something fast. People rewrite subject lines, cut the images, or send less. Sometimes that helps for a week, and then the problem comes back.

The trouble is that several different causes look the same from the outside. Broken authentication, a tired list, and a sudden jump in volume can all show up as the same falling open rate.

So our method is differential diagnosis. The idea comes from medicine: list every condition that could explain a symptom, then rule them out one by one.

In a Klaviyo account, that means you write down every plausible cause before you touch anything. Then you test each one against real data, and you only act on the causes the evidence confirms.

It feels slower at first. In practice it's faster, because you stop fixing things that were never broken. If you'd like the full method in plain language, read the Email DDx framework.

My Klaviyo emails are going to spam

This is the symptom most people search for first. Inbox providers like Gmail, Yahoo, and Outlook move mail to spam when they don't trust the sender enough.

That trust is built from a few things: who you are (authentication and sending history), how people react (clicks, replies, complaints), and what's inside the email. Any of them can break on its own.

Before you change anything, confirm where the mail is actually landing. Ask a handful of recent subscribers, and send a test to seed inboxes you control. "Spam," "Promotions," and "fewer opens" are three different problems with three different fixes.

We cover the five causes that pull Klaviyo mail into spam, and the ten-minute checks for each, in why your Klaviyo emails are going to spam.

My open rate dropped suddenly

A sudden drop feels alarming, but it isn't always a deliverability problem. Sometimes the mail is reaching the inbox just fine and the number itself has shifted.

Start by asking when the drop began and what changed that week. A new template, a bigger send, a list import, or a DNS change are all worth writing down.

Then compare clicks and orders over the same period. If clicks held steady while opens fell, the cause may sit in how opens are counted. If clicks fell too, placement moves higher on your list of suspects.

We'll go through each possible cause in why your Klaviyo open rate dropped.

My open rate looks too good to be true

The opposite problem is just as common, and it's harder to spot. Apple Mail Privacy Protection loads the images in an email, including the tracking pixel, before the reader opens it. Klaviyo's help docs explain that this can record an open even when nobody read the message.

That means a list with many Apple Mail users can look healthy on opens while clicks quietly slide. It also means an "engaged" segment built on opens alone may include people who haven't read anything in months.

Klaviyo tags these as Apple Privacy Opens, so you can split them out in reports and segments. Leaning on clicks and orders gives you a truer picture.

Read more in Apple Mail Privacy Protection and your open rate.

I'm not sure my authentication is set up right

SPF, DKIM, and DMARC are the records that prove your email really comes from you. When one is missing or out of date, inbox providers have less reason to trust the mail.

In Klaviyo, the usual setup is a branded sending domain, often a subdomain like send.yourbrand.com. Klaviyo's docs describe how it lets your mail carry your own domain instead of a shared one.

Seeing "Verified" in Klaviyo is a good start, but it isn't the last check. Send yourself a real email, open the original message, and confirm that SPF, DKIM, and DMARC all pass and line up with your From address.

Recheck after any website move, DNS change, or agency handoff. A step-by-step walkthrough is coming in the Klaviyo SPF, DKIM, and DMARC setup guide.

Gmail or Yahoo seem to be rejecting my mail

Gmail and Yahoo both publish rules for senders. Gmail's guidelines say that anyone sending about 5,000 or more messages a day to personal Gmail accounts must meet a stricter set of requirements.

Those include SPF, DKIM, and DMARC (a policy of p=none is allowed), a From domain that aligns with SPF or DKIM, one-click unsubscribe on marketing mail, and a spam rate in Postmaster Tools below 0.3%. Yahoo's Sender Hub lists a very similar set and asks senders to honor unsubscribes within two days.

When these checks fail at volume, mail can be rejected outright. That can look like an ordinary bounce, so read delivery errors as well as the spam folder.

We'll cover each rule and how to test it on a live email in the Gmail and Yahoo sender requirements for Klaviyo.

I don't know how my sender reputation looks

Sender reputation is how inbox providers judge your past behavior as a sender. It moves slowly, which is why a problem today often started weeks ago.

Google Postmaster Tools is the clearest free view for Gmail. It shows your spam rate, authentication pass rates, delivery errors, and a Compliance status dashboard that checks you against Gmail's sender rules.

Read the trend, not a single day. A complaint rate that creeps up over a month tells you more than one bad send.

We'll walk through each dashboard in how to check your Klaviyo sender reputation.

My spam complaint rate is climbing

Every time someone marks your email as spam, your reputation takes a small hit. Gmail's guidelines ask senders to stay below 0.10% and to avoid ever reaching 0.30%.

Complaints usually rise for reasons you can trace. People forget they signed up, the send frequency jumps, or a giveaway brought in subscribers who never wanted the emails.

Start by checking who received the sends that drew the most complaints. Then look at how often you mailed them and how they joined.

We'll cover causes and fixes in the Klaviyo spam complaint rate guide.

My bounce rate is high

A bounce means the email never reached the person at all. A hard bounce is permanent, like an address that doesn't exist. A soft bounce is temporary, like a full mailbox or a server that's busy.

A rising bounce rate usually points to the list rather than the email. Old imports, typos at signup, and addresses that went stale over time are the common suspects.

Look at where the bouncing profiles came from and when they joined. That tells you whether to fix the signup form, the import, or the cleanup routine.

Read more in why your Klaviyo bounce rate is so high.

My emails land in the Promotions tab

Promotions is still the inbox. The email arrived, and Gmail sorted it into a tab instead of Primary.

That can lower clicks, so it's worth a look, but it's a different problem from spam. Handling it like spam can lead you to rip out content that was working fine.

We'll explain what drives tab placement, and when it matters, in why your Klaviyo emails go to the Promotions tab.

My emails aren't reaching the inbox at all

Low inbox placement is the umbrella symptom. It's what you see when one or more of the causes above has been building for a while.

The fix starts with a placement test. Send the same email to seed inboxes on Gmail, Yahoo, and Outlook, and note where each copy lands. Then line that up with your Postmaster data and your Klaviyo bounce and complaint numbers.

If only one provider is unhappy, the cause is often specific to that provider's rules. If all of them are, look first at authentication and list quality.

We'll go deeper in how to fix low Klaviyo inbox placement.

I just set up a new sending domain

A brand-new branded sending domain has no history yet. Inbox providers watch it closely, and a big first send can make them nervous.

Google's guidelines suggest starting with a low volume to engaged subscribers and raising it slowly. They also warn that suddenly doubling your volume can lead to rate limits or reputation drops.

In Klaviyo, that usually means sending to your most engaged segment first and widening it over the following weeks. Keep a steady rhythm while you do it.

A full schedule is coming in how to warm up a new Klaviyo sending domain.

Klaviyo deliverability checklist

Use this list as a map of the account. It doesn't tell you the cause on its own, but it shows where to look while you test each possible cause.

Authentication

• A branded sending domain is verified and active in Klaviyo.
• A real test email shows SPF, DKIM, and DMARC passing.
• The From domain aligns with the domain that passed SPF or DKIM.
• DMARC is published on your root domain, at least at p=none.

Gmail and Yahoo rules

• One-click unsubscribe headers appear on a real marketing email.
• A visible unsubscribe link sits in the email body.
• Postmaster Tools is connected and the Compliance status is reviewed.

Reputation and complaints

• Postmaster spam rate stays below 0.10%, and never near 0.30%.
• Klaviyo complaint and bounce rates are read as a 30-day trend.
• Sending volume rises gradually, with no sudden spikes.

List quality

• You know how much of each send goes to people who haven't clicked in 90 to 180 days.
• Quiet profiles are suppressed from regular campaigns.
• Giveaway and imported signups are tracked as their own groups.

Measurement

• Apple Privacy Opens are split out from other opens.
• Clicks and orders carry more weight than opens.
• Seed tests on Gmail, Yahoo, and Outlook run after any big change.

If one box fails, write it down as a possible cause. Then test it before you fix it, because two failed boxes can point to the same root cause.

When you'd like a wider view of the whole account, our guide on how to audit Klaviyo covers flows, lists, and tracking too.

Frequently asked questions

What is a good deliverability setup in Klaviyo?

A branded sending domain with SPF, DKIM, and DMARC passing and aligned, one-click unsubscribe on marketing mail, and a list that only gets regular campaigns while people stay engaged. From there, watch your complaint and bounce trends each month.

How do I know if my Klaviyo emails are going to spam?

Ask a few recent subscribers where your last campaign landed, and send the same email to seed inboxes you control. Then check your spam rate in Google Postmaster Tools. Falling opens alone aren't proof, because Apple Mail Privacy Protection can blur that number.

What spam complaint rate is too high?

Gmail asks senders to keep the spam rate in Postmaster Tools below 0.10% and to avoid ever reaching 0.30%. Yahoo also asks bulk senders to stay below 0.3%. A rate that keeps rising is worth checking even while it's still under those lines.

How long does it take to fix Klaviyo deliverability?

Fixing a DNS record can take minutes, but reputation recovers more slowly. Google notes that improvements in spam rate can take time to show up in how your mail is classified. Keep a steady sending schedule while you wait, and avoid a big catch-up send.

Do I need to follow the Gmail and Yahoo bulk sender rules?

Gmail applies its stricter rules once you send about 5,000 or more messages a day to personal Gmail accounts. Many of the same steps, like authentication and easy unsubscribes, are good practice at any size.

Sources

• Google, Email sender guidelines (Gmail Help): https://support.google.com/a/answer/81126
• Google, Postmaster Tools dashboards (Gmail Help): https://support.google.com/mail/answer/14668346
• Yahoo, Sender Best Practices (Sender Hub): https://senders.yahooinc.com/best-practices/
• Klaviyo Help Center, How to identify iOS15 Mail Privacy Protection opens: https://help.klaviyo.com/hc/en-us/articles/4416791883163
• Klaviyo Help Center, How to set up a branded sending domain: https://help.klaviyo.com/hc/en-us/articles/115000357752

Find the cause before you change the email

Deliverability problems feel urgent, and that's exactly when it pays to slow down for an hour. Write down what changed, list every cause that could explain it, and test them one at a time.

If you'd like a second pair of eyes, a Klaviyo audit from EmailDDx works through the same steps on your own account. We'll show you which causes the data confirms and which ones you can safely set aside.