Email Deliverability

Definition

A soft bounce is a temporary email delivery failure that occurs when an email cannot be delivered due to a temporary issue, such as a full mailbox, server downtime, or message size limits. Soft bounces may succeed on retry.

Common Causes of Soft Bounces

Recipient's mailbox is full

Email server is temporarily unavailable

Message is too large for the recipient

Recipient's server is experiencing high load

Temporary DNS issues or network problems

Why Soft Bounces Matter

While soft bounces are less severe than hard bounces, repeated soft bounces indicate underlying issues. A mailbox that's consistently full may be abandoned. A server that's always down may no longer exist. Ignoring soft bounces can lead to list decay and eventual hard bounces.

How to Handle Soft Bounces

Allow your ESP to retry delivery automatically (usually 3 attempts)

Track consecutive soft bounces for each address

Convert to hard bounce after 3-5 consecutive soft bounces

Remove addresses that soft bounce on every campaign

Investigate sudden spikes in soft bounce rates

Frequently Asked Questions

Should I remove soft bounces from my list?

Not immediately. Give soft bounces a chance to resolve. If an address soft bounces 3-5 times consecutively across multiple campaigns, treat it as a hard bounce and remove it.

What causes a sudden increase in soft bounces?

Sudden soft bounce spikes often indicate recipient server issues, temporary blacklisting, or problems with your sending infrastructure. Check if the bounces are concentrated on one domain and investigate accordingly.

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