Deliverability

Soft bounce vs hard bounce — what they mean and what to do

A hard bounce is a permanent failure (bad address) — suppress it immediately. A soft bounce is temporary (full mailbox, server down) — retry a few times, then suppress. Confusing them wrecks deliverability.

16 Jun 2026 5 min readBy Autocloz Editorial, Deliverability team
Soft bounce vs hard bounce — what they mean and what to do

Short answer: a hard bounce is a *permanent* delivery failure (the address doesn't exist or rejects you) — suppress that contact immediately and never email it again. A soft bounce is *temporary* (mailbox full, server briefly down, message too large) — retry a few times over a day or two, then treat persistent soft bounces as hard. Continuing to hit hard bounces is the fastest way to lose inbox placement.

What to do with each

  • Hard bounce → suppress instantly; it counts heavily against reputation.
  • Soft bounce → retry 2–3 times; if it keeps failing, suppress.
  • Track the rate → keep total bounces under 2.5%.

Why it matters

Mailbox providers watch your bounce rate as a spam signal. Verifying lists before sending prevents most hard bounces; smart retry logic handles soft ones.

Autocloz classifies every bounce and auto-suppresses hard bounces, retries soft ones, and auto-pauses a mailbox if bounces spike.

> Start free — bounce handling + suppression on autopilot.

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Every tactic in this article is implemented behind the Autocloz dashboard.