What Is a Soft Bounce?
A soft bounce happens when an email you send reaches the recipient's mail server but cannot be delivered at that moment. Unlike a hard bounce, where delivery fails permanently because the address does not exist, a soft bounce is a temporary obstacle. The address is real and valid. The message simply could not get through right now.
The most frequent cause of a soft bounce is a full inbox. If a subscriber has not cleared their mailbox in some time, the server will reject incoming messages until space is freed up. Other causes include the recipient's mail server being temporarily down for maintenance, content filtering rules on the server side that block the message, or the email itself exceeding the maximum permitted size for that server. Some corporate mail servers in South Africa use strict filtering policies, particularly in financial services or government sectors, and can soft-bounce messages from unfamiliar domains even when the content is completely legitimate.
Email service providers handle soft bounces differently from hard bounces. Most platforms will automatically retry delivery of a soft-bounced message several times over the next 24 to 72 hours. If the issue resolves, the message is delivered successfully. Only after repeated failed attempts across multiple campaigns does the platform flag the address for suppression. This makes soft bounces far less immediately damaging to your sender reputation than hard bounces, but they are still worth monitoring closely.
Soft Bounce In Practice
Imagine a Pretoria-based financial services firm sending a monthly newsletter to 5,000 subscribers. On sending day, 120 addresses soft-bounce. The platform retries automatically and 90 of those addresses receive the message within 48 hours. The remaining 30 continue to soft-bounce across the next two or three campaigns. After the third consecutive soft bounce, the platform suppresses those addresses because the pattern suggests the accounts may be abandoned or the mailboxes are chronically full, meaning the subscribers are no longer active.
For South African businesses, the practical lesson is to monitor your bounce reports after every send. Most email platforms display hard and soft bounces as separate categories in your campaign statistics. A sudden spike in soft bounces for a segment of your list can point to a technical issue on the recipient's infrastructure rather than a problem with your content or email deliverability. Consistent soft bounce rates above 1% warrant a list re-engagement campaign to identify which subscribers are still active and worth retaining, and which should be removed to keep your list healthy.
Soft bounce versus hard bounce
A soft bounce is an email that could not be delivered for a temporary reason, so a later attempt might succeed. Common causes are a full mailbox, a server that is temporarily down or overloaded, or a message too large for the recipient's limits. This distinguishes it from a hard bounce, a permanent failure such as an invalid or non-existent address, which will never deliver. The distinction shapes how you respond: a hard bounce should be removed from the list immediately, because it will never succeed and mailing it harms your reputation, whereas a soft bounce can be retried, since the obstacle may clear. Email systems typically retry soft bounces automatically for a period before giving up. Understanding which kind of bounce you are seeing prevents both the mistake of removing recoverable addresses and the mistake of repeatedly mailing dead ones.
How to handle soft bounces
Soft bounces are usually handled automatically by email platforms, which retry delivery over a period in case the temporary problem, a full mailbox, a busy server, resolves. The key judgement is when a soft bounce has stopped being temporary: an address that soft-bounces repeatedly across several sends is effectively undeliverable, and continuing to mail it wastes sends and signals poor list quality, so persistent soft bouncers should eventually be treated like hard bounces and removed. A common practice is to set a threshold, removing an address after it soft-bounces a certain number of consecutive times. Monitoring soft-bounce patterns also helps diagnose wider problems: a sudden rise in soft bounces can indicate a deliverability issue, such as a reputation problem causing servers to defer your mail, worth investigating rather than ignoring, since it may affect more than the bouncing addresses.
FAQ
How many soft bounces before you remove an address?
Most email service providers automatically suppress an address after three to five consecutive soft bounces over a set period. The logic is that repeated soft bounces suggest the account may have been abandoned or the mailbox is persistently full, which means the address is unlikely to yield engagement.
Do soft bounces affect sender reputation?
Soft bounces have a smaller impact than hard bounces, but a consistently high soft bounce rate still signals list quality problems to inbox providers. Keeping your overall bounce rate below 2% across both hard and soft bounces is important for protecting deliverability and inbox placement.
How many soft bounces before removing an address?
A common approach is to remove an address after it soft-bounces a set number of consecutive sends, often several, since by then the failure is effectively permanent. Email platforms handle retries automatically; the judgement is when a repeatedly soft-bouncing address should be treated like a hard bounce and removed.