There are 2 types bounces return, soft and hard.
There are 2 types of bounces return, soft or hard ones.The hard bounces code are returned where it was impossible to deliver the email in the mailbox because customer's mailbox does not exist. These are the equivalent of our IASP for our physical letters
Hard bounces are returned when it was impossible to deliver the email into the mailbox because the customer's mailbox does not exist. These are the equivalent of IASP for mail.Soft-bounce returns occur when the email can not be delivered temporarily, for example if the recipient's mailbox is full. Unlike a hard bounce-back, it can be sent over again later on.
For extra info on bounces and the way they are processed, consult our dedicated online help and read the article