Are soft bounces harmless?

Myth: Soft bounces are harmless.

Reality: Soft bounces have real impact:

Individual soft bounce:

Typically temporary and recoverable. Retry should succeed. Single occurrence is not concerning.

Accumulated soft bounces:

Pattern indicates problems. May mask abandoned addresses. Contributes to negative reputation signals. Wastes sending resources.

Soft-to-hard escalation:

Persistent soft bounces convert to hard. Mailbox full for months means abandoned. Repeatedly throttled suggests issues.

ISP perspective:

High deferral rates are suspicious. Indicates potential list quality issues. May trigger throttling.

Best practice:

Track soft bounces per address. Suppress after threshold. Investigate persistent patterns.

Soft bounces are symptoms, not harmless noise. Pay attention to what they reveal.