In plain English
The mailbox is full, the server is unavailable, or the message was too large. The address is valid and delivery may succeed on a later attempt.
Platforms retry automatically for a period. If an address soft bounces repeatedly across several sends, it should be treated as permanently undeliverable.
What to know
Temporary
Delivery may succeed later.
Common causes
Full mailbox, server down, message size.
Retried automatically
By most sending platforms.
Repeated soft bounces
Should be suppressed like hard bounces.
Why it matters
Soft bounces are usually harmless individually and meaningful in aggregate. A rising soft bounce rate to one domain often indicates a filtering problem rather than a mailbox problem.
Common mistakes
×Ignoring repeated soft bounces to the same address.
×Assuming all soft bounces are harmless.
×Missing a pattern concentrated at one provider.
×No suppression rule after repeated failures.
FAQs
How many soft bounces before removing an address?
Three to five consecutive failures is a common threshold.
Do soft bounces hurt deliverability?
Individually no. Persistently high rates do.
WRITTEN BY TARIQ SALLAM
Marketing Consultant. Entrepreneur. Content Creator.
I'm a marketing consultant, entrepreneur and content creator. I help businesses grow through practical marketing, websites, SEO, content and AI.
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