Why Your Klaviyo Emails Are Landing in Spam

When email revenue drops, most people look at subject lines first. Subject lines matter, but they only matter for emails that reach the inbox. If your emails are landing in spam or promotions, no subject line will fix that.

The problem is that Klaviyo will not tell you this directly. It shows you 'Delivered,' which just means a mailbox provider accepted the email onto its servers. It says nothing about which folder it landed in.

"Delivered" is not the same as "inbox"

This is the gap that trips up most store owners. Your dashboard shows a 98% delivery rate and everything looks fine. Meanwhile a growing share of those 'delivered' emails are sitting in spam, where nobody opens them, nobody clicks them, and your open rate slowly drifts down for reasons that look mysterious.

You can check actual inbox placement with a seed test: send a campaign to a handful of Gmail, Yahoo, and Outlook accounts you control and see where it lands. Google Postmaster Tools will also show you a domain reputation score if you send from a Gmail-hosted domain or route enough Gmail traffic.

The five most common causes

In order of how often we see them:

• Missing or misconfigured SPF, DKIM, or DMARC records at the DNS level
• A sudden spike in send volume or frequency without a warm-up period
• Sending regularly to subscribers who have not opened an email in 90+ days
• A list built partly on old imports, contests, or purchased data
• High complaint or bounce rates from a single recent campaign that damaged domain reputation

Fix the foundation before the flows

It is tempting to jump straight to rewriting flows when revenue is down. But if your emails are not reaching the inbox, a better welcome series will not save you. Deliverability problems compound: the more that lands in spam, the worse your engagement signals look, the more mailbox providers filter you, and the worse it gets.

The fix order that actually works: verify DNS authentication first, then clean up list hygiene and suppress the unengaged, then rebuild or improve flows. Doing it in the reverse order means optimizing content that most of your list will never see.

Why this is easy to miss for months

Klaviyo has no way to warn you about this. It can see everything happening inside your account, but SPF and DMARC records live in your domain's DNS, a completely different system that Klaviyo has no visibility into. Even Klaviyo's own native audit tool, which checks your flows and account setup, cannot look outside your account to see whether your domain is actually authenticated correctly. A brand can have every flow built perfectly and still be quietly bleeding revenue to spam folders for months before anyone notices.

This is also why deliverability problems are dangerous even when nothing changed on your end. A DMARC policy can lapse, a DNS record can get overwritten during an unrelated change, or a registrar migration can quietly drop a TXT record, and nothing in Klaviyo will tell you. The account keeps sending, the dashboard keeps saying 'Delivered,' and inbox placement keeps sliding.

The shortcut

Checking DNS records manually means logging into your domain registrar and reading TXT records, which is not most people's idea of a good afternoon. FlowScore checks your SPF and DMARC setup automatically against your actual domain's DNS records, flags exactly what is missing or misconfigured, and gives you a recommendation for DKIM through Klaviyo's own domain settings. On paid plans, it re-checks those records on a schedule and emails you if something breaks, so a lapsed DMARC policy gets caught the day it happens instead of three months later when someone finally asks why open rates fell off a cliff.