What is the difference between a hard and soft bounce?

A ‘bounce’ means that your newsletter was sent to a specific email address but the mail server (from the recipient side) sent it back, saying it could not be delivered.

There might be different reasons why this happened and they’re divided in two main categories:

Soft bounce

A soft bounce is an email message that gets as far as the recipient’s mail server (it recognizes the address) but is bounced back undelivered before it gets to the intended recipient. A soft bounce might occur because the recipient’s mailbox is full, the server is down or swamped with messages, or the message is too large.

If an email has soft bounced in the last 5 campaigns without any trackable activity like an open or a click (and if those 5 campaigns took place over more than 2 days) it will automatically be converted to a hard bounce and be removed from your list.

Hard bounce

A hard bounce is an email message that has been returned to the sender and is permanently undeliverable. Causes include invalid addresses (domain name doesn’t exist, typos, changed address, etc.) or the email recipient’s mail server has blocked your server.

Servers can sometimes interpret bounces differently, meaning a soft bounce on one server may be classified as a hard bounce on another.

Our email sending application automatically moves subscribers that hard bounce into a “Bounced Subscribers” category, so they don’t receive future campaigns.

This ensures the quality of the sending servers and the trustworthiness of your domain.