What is a Soft Bounce / Hard Bounce / Opt Out?

An Opt Out means that a member has unsubscribed by clicking the unsubscribe link at the bottom of the email sent. 

A Soft Bounce means that the email address was valid and the email message reached the recipient’s mail server. However, it bounced back because:

  • The mailbox was full (the user is over their quota)
  • The server was down
  • The message was too large for the recipient’s inbox

Therefore a Soft Bounce is an email that is recognized by the recipient’s mail server but is returned to the sender because the recipient’s mailbox is full or the mail server is temporarily unavailable. A soft bounce message may be deliverable at another time or may be forwarded manually by the network administrator in charge of redirecting mail on the recipient’s domain.

A Hard Bounce occurs when the message has been permanently rejected either because:

  • The email address is  invalid
  • The email addresses doesn’t exist

Therefore a Hard Bounce is an email that permanently bounced back to the sender because the address is invalid. A hard bounce might occur because the domain name doesn’t exist or because the recipient is unknown.  Some mail servers may hard bounce an email address if the message received is suspected as spam.

Soft bounces are blocks that are a short term issue–you don’t need to permanently take these addresses off of your list. However, hard bounces are either invalid or non-existent addresses that should be removed immediately.