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Deliverability

Why your emails land in spam (and how to fix it)

MO
Written by
Maya Okonkwo · Head of Deliverability
Mar 14, 2026 · 6 min read

Landing in spam is rarely about one thing. It's usually a stack of small problems — authentication, reputation, list quality and content — adding up. Here are the common causes and their fixes.

Authentication gaps

Missing or misconfigured SPF, DKIM or DMARC makes your mail look spoofable, and bulk providers now require all three. Fixing authentication is often the single biggest jump in inbox placement.

A dirty list

Bounces and spam-trap hits from unverified lists are among the fastest ways to get filtered. Verify before every send so invalid and risky addresses never enter the campaign.

Poor engagement

If recipients don't open, click or reply — and especially if they mark you as spam — providers learn to filter you. Mail people who opted in, prune the unengaged, and make unsubscribing easy.

Spammy content and sending patterns

  • ALL-CAPS subject lines and excessive punctuation.
  • Sudden volume spikes from a cold domain.
  • Link shorteners and risky attachments.
  • No clear unsubscribe option.
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