deliverability

Why your emails land in spam (and the 5 fixes that actually matter)

May 12, 2026

Deliverability isn’t magic, and it isn’t luck. Inbox providers score every message on a handful of signals, and most stores fail the same five. Fix these and you’re ahead of 90% of senders.

1. Authenticate your domain (DKIM)

Until you verify a sending domain, you’re borrowing someone else’s reputation. Gmail and Yahoo now require DKIM-aligned sending for bulk senders. Verification takes one DNS record and ten minutes. In AguMail it’s Settings → Your domain → Add domain, and we re-check your DNS automatically until it flips green.

While you’re unverified, AguMail caps your sends (100 per campaign, 300 per day) on a shared domain. That cap isn’t a paywall — it’s protection. One bad blast from an unauthenticated sender can poison weeks of inbox placement.

2. Send to people who said yes

The single biggest spam-folder predictor is sending to people who don’t remember subscribing. Purchased lists, scraped lists, and “I imported my old CRM” lists generate complaints — and complaint rate above ~0.1% gets you filtered everywhere.

This is why AguMail quarantines risky imports and never assumes consent on store-synced contacts: a customer is not a subscriber until they opt in.

3. Keep a clean list without being asked

Hard bounces tell providers you don’t know your own audience. Suppress them instantly (AguMail does this on the first bounce) and pause campaigns automatically when the bounce rate spikes — ours trips at 5%.

4. Make unsubscribing trivial

Counter-intuitive but true: an easy unsubscribe protects you. Subscribers who can’t find the link click “mark as spam” instead, which costs you a hundred times more. Every AguMail email carries the one-click List-Unsubscribe header plus a footer link to a preference center — letting people pause for 30 days or pick topics instead of leaving entirely.

5. Warm up, don’t blast

A brand-new domain that sends 50,000 emails on day one looks exactly like a spammer. Ramp up: most-engaged segment first, then widen. Watch opens directionally (Apple Mail Privacy inflates them) and treat clicks as your truth metric.

AguMail bakes all five into the product — DKIM verification with live DNS checks, consent-aware imports, automatic suppression, one-click unsubscribe, and bounce-rate auto-pause. Start a free trial — no card to start.