Problem
Klaviyo emails going to spam: how to fix it
Mailbox providers decide where your email lands using two things: whether they can verify you sent it, and how people have responded to you before. Authentication is a configuration task you can finish in a day. Reputation is behaviour, and it takes weeks of consistent sending to shift. Fix the first completely, then work on the second, because reputation work on an unauthenticated domain achieves nothing.
By CartKernel · Last reviewed 2026-09-07
Does this look familiar?
- Open rates fell sharply while send volume and list size stayed the same
- Campaigns land in the promotions or spam folder in your own test inboxes
- One mailbox provider performs much worse than the others
- Bounce rates or spam complaint rates rose over recent sends
- Deliverability fell after a large import, a list purchase or a long gap in sending
- Click rates held for engaged subscribers while overall opens collapsed
Causes, ranked
Why it happens, most common first
Check them in this order. The first two account for most cases we open.
- most common
Sending authentication is incomplete
Bulk senders are expected to authenticate with both signing and sender policy records, and to publish a policy record at the domain level. A store still sending from the platform's shared domain, or with records that were added and later broken by a DNS change, will be filtered regardless of content.
- most common
The list includes people who never engaged
Sending to everyone who ever gave an address, including old imports and addresses collected without clear permission, produces low engagement and complaints. Mailbox providers read that as unwanted mail and route future sends accordingly, including to people who do want them.
- common
Complaint rate is above what providers tolerate
Major providers publish a spam complaint threshold for bulk senders, commonly cited as three complaints per thousand messages. Sends that cross it are filtered, and the effect persists after the offending campaign. Complaints usually come from unexpected frequency or unclear signup.
- common
Volume changed abruptly
A new sending domain used at full volume, a return to sending after months of silence, or a sudden send to the whole list after months of segmented sends all look like a compromised account. Providers respond by filtering until the pattern settles.
- common
Unsubscribing is harder than complaining
Bulk senders are expected to support one click unsubscribe from the message itself and to honour it promptly. When the visible option is a small link to a preference centre that asks for a login, people press the spam button instead, which is far more damaging.
- occasional
Content and links raise filtering signals
Messages that are a single large image with almost no text, links pointing at domains unrelated to the sender, shortened links, and heavy discount language in subject lines all contribute. These matter mostly when reputation is already marginal rather than on their own.
- occasional
Bounces and invalid addresses are not being cleaned
Repeatedly sending to addresses that hard bounce signals a list that is not maintained. Most platforms suppress these automatically, but addresses imported from another system or re-added by an integration can reintroduce them.
The fix
In this order
Each step is something you can do today. Do them in sequence; skipping ahead is how a review fails twice.
Prevent it next time
- Monitor spam complaint rate, bounce rate and domain reputation weekly rather than after a problem
- Keep authentication records under change control so a DNS edit cannot silently break them
- Segment by engagement on every campaign rather than sending to the full list by default
- Review the signup sources feeding the list quarterly and remove any that produce complaints
Complete sending domain authentication
Set up a branded sending domain and publish the signing and sender policy records the platform provides, then add a policy record for the domain and set it to monitor before enforcing. Verify with an external checker rather than trusting the interface alone.
Register with provider postmaster tools
Add and verify your sending domain with the major providers' sender tools so you can see domain reputation, spam rate and authentication results from their side. Without that view you are guessing at what they think of you.
Stop sending to unengaged addresses immediately
Build a segment of people who have opened or clicked recently, or purchased, and send only to that group while you recover. Define recent according to your sending frequency rather than a fixed number of days.
Set up a sunset flow
Create an automated path that gives long term non openers a final chance to confirm interest, then suppresses them. This keeps the list to people who want the mail and protects the reputation of every future send.
Make unsubscribing effortless
Enable the header that supports one click unsubscribe, put a plain unsubscribe link in the footer of every message, and honour requests promptly. Offering a frequency choice alongside is fine, provided a single click unsubscribe is still available.
Rebuild volume gradually
Increase send volume in steps over several weeks, starting with the most engaged segment and widening as reputation improves. Keep the schedule consistent, since irregular bursts are read as suspicious even when the content is good.
Improve the messages themselves
Use a real text to image balance, link only to your own domains, write subject lines that describe the content rather than shouting an offer, and make the sending name and address recognisable. Send a plain text alternative alongside the styled version.
Fix how addresses enter the list
Use confirmed opt in where the source is uncertain, set expectations at signup about what will arrive and how often, and stop importing addresses collected without permission. Every future problem starts here.
When to get help
Bring in help when reputation has already been damaged and revenue from email has fallen, because recovery needs a deliberate sequence of suppression, segmentation and gradual volume rebuilding, and mistakes during that period extend it. It is also worth help when the store sends from a domain shared with transactional mail or with a parent company, since separating subdomains and policies properly protects the mail that customers must receive, such as order confirmations.
Free. We reply within one business day.
Should I send marketing email from my main domain or a subdomain?
Use a subdomain for marketing and keep transactional mail on its own path. That way a reputation problem in campaigns does not put order confirmations and password resets at risk. Both should be authenticated, and the policy record at the top level should cover them.
How long does deliverability take to recover?
Expect several weeks of consistent, well received sending before reputation improves noticeably, and longer if complaints were high. There is no way to accelerate it beyond sending good mail to people who want it. Recovery shows first in engagement from your most active segment.
Do I need a dedicated sending IP address?
Only at high, consistent volume. A dedicated address needs enough regular sending to build its own reputation, and a store sending irregularly is usually better served by a well managed shared pool. Domain reputation matters more than the address for most senders now.
Does landing in the promotions tab count as going to spam?
No. The promotions tab is an inbox folder where shoppers routinely look for offers, and mail there is delivered normally. Chasing placement in the primary tab is usually a poor use of effort. Judge performance on clicks and revenue per recipient rather than on which tab it landed in.
Services that fix it for good
Related problems, answers and terms
Stop the leak.
A free Growth Analysis finds what is broken and ranks it by the revenue it costs you.