Klaviyo or Mailchimp emails going to spam? How to fix it

Updated 10 November 2026 · by Mohamed, Growth with MK

Your campaigns go out, open rates drop, and test emails land in spam. Or Gmail shows "via" and another domain next to your brand name. With Klaviyo, Mailchimp, Brevo and similar tools, this usually comes down to authentication first and list quality second.

Why it happens

Out of the box, email platforms send your campaigns from their shared infrastructure and sign them with their own domain. That works, but your emails don't build trust for your domain, and Gmail may show "via" with the platform's domain. Since February 2024, Gmail and Yahoo require bulk senders to have SPF, DKIM and DMARC with alignment to the From domain, plus one-click unsubscribe. Microsoft followed for Outlook.com in May 2025.

Fix 1: authenticate your domain in the platform

Klaviyo: set up a branded sending domain, usually a subdomain such as send.yourbrand.co.uk. Klaviyo gives you DNS records to add, and the subdomain must share the root domain of your From address (hello@yourbrand.co.uk).
Mailchimp: go to the domains settings, verify your domain, then Authenticate. Mailchimp gives you CNAME records for DKIM and checks for a DMARC record.
Brevo, MailerLite and others: look for "authenticate domain" or "sender domain". The process is the same: add the records, then press verify.

Fix 2: DMARC on your root domain

Add a TXT record at _dmarc: v=DMARC1; p=none; rua=mailto:you@yourdomain. Of 747 UK small-business domains we checked in November 2026, 46% had none, which is enough on its own to fail Gmail's bulk sender rules.

Fix 3: don't send from a free address

A gmail.com, yahoo.com or hotmail.co.uk From address can't be authenticated by your platform. Yahoo publishes a DMARC policy of p=reject, so receivers are told to refuse mail that claims to be from a Yahoo address but wasn't sent by Yahoo. Most platforms rewrite or block free From addresses for this reason. Always use your own domain.

Fix 4: list and content hygiene

Only email people who opted in. Never upload bought or scraped lists.
Suppress unengaged subscribers. A common starting point is people who haven't opened or clicked in 90 to 180 days (bearing in mind Apple Mail Privacy Protection inflates opens), after a final win-back email.
Keep spam complaints under 0.1%. Make the unsubscribe link easy to find.
Warm up a new sending domain by sending to your most engaged subscribers first and increasing volume over a few weeks.
Balance images and text, and avoid link shorteners.

Check it worked

Send a campaign test to Gmail → Show original. You want SPF, DKIM and DMARC to pass, with DKIM showing your domain (d=yourbrand.co.uk), not the platform's. Then run the free domain check on your root domain.

On Shopify? Also read Shopify emails going to spam. Transactional emails missing too? See order confirmation emails not received.

Frequently asked questions

How do I remove "via" next to my name in Gmail?

Authenticate your domain in the sending platform so it signs with your domain's DKIM instead of its own. Once DKIM aligns with your From address, Gmail stops showing "via".

Should I use a subdomain for marketing email?

Often, yes. Klaviyo's branded sending domain uses one (for example send.yourbrand.co.uk). It keeps marketing reputation a little separate from your everyday mailbox while still aligning with your root domain.

Why do my test emails go to spam when real campaigns don't?

Tests are often sent to a handful of internal addresses with no engagement history, sometimes with placeholder content. Judge deliverability on real campaign results and Gmail's "Show original" checks.

How long until inbox placement improves?

Authentication takes effect within hours of the DNS records going live. Reputation recovers more slowly, usually over a few weeks of sending to engaged subscribers.

Check your domain in 10 seconds

See your DMARC, SPF, DKIM and MX score out of 10, with fix steps for your email provider.

Run the free check