Why It Matters
Soft bounces are normal in small numbers — every list will have some. But if your soft bounce rate climbs above 5%, something's wrong. It could mean you're sending to a lot of inactive accounts, hitting rate limits, or your reputation is causing servers to temporarily reject you. Left unchecked, repeated soft bounces to the same address can eventually be treated like hard bounces by your ESP.
How It Works
When your email server gets a 4xx SMTP response code, that's a soft bounce. The receiving server is saying "not right now, try again later." Your sending platform will typically retry 3-5 times over 24-72 hours. If it eventually gets through, great — no harm done. If all retries fail, the address gets flagged. Most ESPs will convert a consistently soft-bouncing address to a hard bounce after a set number of failures.
Quick Tips
- Don't immediately remove soft-bounced addresses — give your platform time to retry.
- If the same address soft-bounces on 3+ consecutive campaigns, remove it manually.
- A sudden spike in soft bounces across your whole list usually points to an IP or domain reputation problem, not a list quality issue.