Hard bounce and soft bounce

Bounces indicate that the recipient's email address cannot be reached, temporarily or permanently. There are two types of bounce for email addresses:

• The “soft bounce”indicates temporary unavailability. This type of bounce happens when the recipient's inbox is full. The typical case is when the recipient has gone on holiday and emails end up filling up their mailbox. A soft bounce can also happen in the event of a connection error, for example due to a server outage.
• The “hard bounce”indicates that the contact's mailbox is permanently unavailable. Either the email address does not exist or it has been deactivated.

The bounce rate combines both categories of bounce. However, it is important to distinguish between them because hard bounces are much more problematic: the contact needs to be updated, or even deleted if their new email cannot be found.