Soft Bounce

A temporary delivery failure caused by full inboxes, server issues, or message size limits.

1 min readLast updated Apr 2026

Reviewed by Golden Digital·Operator-reviewed ecommerce reference

Quick Reference

CategoryEmail Marketing & Klaviyo

Related Terms2

A temporary delivery failure caused by full inboxes, server issues, or message size limits.

Why It Matters

Soft bounces are temporary—but repetitive soft bounces to the same address indicate a dead inbox. ESPs typically retry soft bounces automatically, but addresses that consistently soft bounce should eventually be suppressed to protect deliverability.

Practical Example

Scenario

A beauty brand notices one email address has soft bounced on 5 consecutive campaigns.

Calculation

Automatic retries have failed repeatedly over 3 months

Result

This 'temporary' issue has become permanent—the inbox is likely abandoned. Moving it to suppression list prevents future deliverability damage.

Pro Tips

1Let your ESP handle soft bounce retries automatically (usually 24-72 hours)
2Suppress addresses after 3 consecutive soft bounces—they're likely inactive
3Check message size if you see unusual soft bounce spikes—large images can trigger limits
4Monitor for patterns—if one ISP shows high soft bounces, there may be a server-side issue

Common Mistakes to Avoid

Treating soft bounces as 'no big deal' and never cleaning them up

Manually retrying soft bounces immediately instead of letting ESP handle timing

Not tracking soft bounce frequency per contact over time

Frequently asked questions

After 3 consecutive soft bounces across different sends (not retries of the same send), move to suppression. This typically means the inbox is full/abandoned for weeks or months.

A full inbox (soft bounce) that remains full for extended periods may eventually have the account deleted by the provider, turning it into an invalid address (hard bounce).

Put it to work

Related Terms

Hard Bounce

A permanent delivery failure typically caused by invalid email addresses.

Bounce Rate (Email)

The percentage of emails that failed to deliver, including hard and soft bounces.

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