Klaviyo Emails Going to Spam? The One Setup Step Most Brands Miss

You have written the emails. You have picked the products. You hit send, and then you sit there wondering why almost nobody is opening them.

Before you blame your subject lines or your list, check one thing. If your Klaviyo emails are going to spam, the most common reason has nothing to do with your copy. It is a technical setup step that a lot of brands never complete, and until it is fixed, even a brilliant email is a waste of money.

Let me walk you through what it is, why it matters so much, and how to sort it.

Quick answer: why are my Klaviyo emails going to spam?

The most common reason Klaviyo emails go to spam is an unauthenticated sending domain. Without it, inboxes cannot confirm the email genuinely came from you, so they treat it as suspicious and filter it out. Authenticating your sending domain proves you own your domain and are sending from your own address, not from a shared Klaviyo one. It is the single biggest deliverability fix for most product brands, and it needs doing before you send anything.

What is a sending domain, in plain English?

A sending domain is proof that you own the email address you are sending from.

Here is what happens without it. When you send from Klaviyo, the email technically goes out through Klaviyo’s servers. If you have not authenticated your domain, inboxes look at that email and think, we are not sure this is really from this brand, it could be someone pretending. So they play it safe and drop you in spam, or block you entirely.

Authenticating your sending domain connects the two. It tells Gmail, Outlook and the rest: yes, this brand owns this domain, and yes, this email is really from them. You are no longer sending from a generic Klaviyo address. You are sending from you, verified.

Without an authenticated sending domain, you are not fighting an uphill battle to reach the inbox. You are being stopped at the door.

How do I know if my sending domain is set up?

You can check inside Klaviyo under your account settings, in the domains or deliverability area. It will either show your domain as authenticated, or it will flag that it is not set up.

A few warning signs that it is probably not done, or not done correctly:

• Your open rates are suspiciously low across the board, not just on one email.
• You have never touched your domain registrar or DNS settings since connecting Klaviyo.
• You set up Klaviyo yourself (or through a third-party app) and clicked through a lot of steps you did not fully understand.
• Emails to your own inbox land in spam or promotions and never in the main tab.
  
  

If any of that sounds familiar, this is very likely your problem, and the good news is it is fixable.

How do I fix a sending domain that has not been authenticated?

The fix lives in two places: Klaviyo and your domain registrar.

Your domain registrar is wherever you bought your domain name. Think GoDaddy, Crazy Domains, Namecheap, or whoever you paid for your web address. Inside that account are your DNS records, which are basically the settings that tell the internet how your domain works.

To authenticate, you copy a set of records that Klaviyo gives you and paste them into your DNS records at the registrar. That is what links the two together and proves ownership. It is a fair bit of careful copy-pasting, and it needs to be exact, but it is not complicated once you know where everything lives.

A few practical notes:

• You will need login access to your domain registrar, not just Klaviyo. This is the step people get stuck on, because they cannot remember where they bought the domain or who set it up.
• If you have two-factor authentication on the registrar (you should), keep your phone or email handy to approve the login.
• Once the records are in, it can take a little time to fully activate while the internet catches up. That is normal.
  
  

If DNS records and registrars make your eyes glaze over, you are not alone, and this is genuinely one of the best things to hand to someone who does it all day. Want a quick, honest read on whether your deliverability setup is costing you sales? A Mini Klaviyo Audit will tell you exactly what is working and what is not.

What about third-party apps that send through my domain?

This is worth a mention, because it is becoming more common. Some brands connect third-party tools, collaboration networks or AI-driven apps that send email through their Klaviyo account and their domain.

The catch is that anything sending under your domain affects your reputation. If those emails are poorly set up, or your domain is not properly authenticated underneath them, it can drag down your inbox placement and you may not even realise it is happening. If you are running something like that, make sure your sending domain is authenticated first, and keep an eye on what is actually going out under your name.

Why does this matter more than my subject lines?

Because none of the clever stuff works if the email never arrives.

You can obsess over subject lines, segmentation and gorgeous design, and you should care about all of it. But deliverability comes first in the order of operations. An unopened email in a spam folder converts at zero, no matter how good it is. Fix the foundation, and suddenly all your other efforts start actually reaching people.

This is why we set up the sending domain as the very first job in any account, before a single email goes out. There is no point building beautiful flows and campaigns if they are landing in junk.

Key takeaways

• If your Klaviyo emails are going to spam, an unauthenticated sending domain is the most likely cause.
• A sending domain proves you own your address, so inboxes trust your email instead of filtering it out.
• Fixing it means copying DNS records from Klaviyo into your domain registrar. It must be exact.
• You need access to your domain registrar, not just Klaviyo, to complete the setup.
• Deliverability comes before subject lines and design. An email in spam converts at zero.