Spam placement is almost always a sender reputation or authentication problem, not a content one. Fix these in order.
2026 reality Gmail and Yahoo require bulk senders to authenticate with SPF, DKIM, and DMARC, keep spam complaints under 0.3%, and include one-click unsubscribe. Missing any one of these is enough to be filtered.
Step 1: Authenticate Your Domain
This is the single biggest fix. In Brevo, add and verify:
- SPF: authorizes Brevo to send for your domain.
- DKIM: cryptographically signs your mail.
- DMARC: tells inbox providers what to do with unauthenticated mail, and must align with your From domain.
Send from your own domain ([email protected]), never from a free address like gmail.com.
Step 2: Add One-Click Unsubscribe
Ensure your campaigns include a working list-unsubscribe header and a visible unsubscribe link. Brevo adds this automatically; do not remove it.
Step 3: Clean the List
Engagement is now a primary filter signal.
- Remove hard bounces and never re-add them.
- Apply a sunset policy: stop emailing contacts who have not opened in 6 to 12 months.
- Only email people who opted in. Purchased lists destroy reputation.
Because Tajo syncs real Shopify behavior, segment to engaged buyers instead of blasting the whole list.
Step 4: Warm Up and Stay Consistent
A new domain or sudden volume spike looks like spam. Increase volume gradually and keep a steady cadence rather than rare large blasts.
Step 5: Re-Test
Send to a seed set across Gmail, Outlook, and Apple Mail. If still filtered, check your domain and IP against major blocklists and review subject lines for obvious spam triggers.
See also improve email deliverability.