The purpose of this article is to explain how email bounces are handled within the RelationshipBuilder platform. This handling is done automatically at a system level but it is important for you to understand what happens when a message to a subscriber bounces and the consequences of having too many bounces.

What is a bounce?

An undeliverable or bounced email is one that never arrives at the recipient’s mail server. When a newsletter email is sent through RelationshipBuilder, a recipient's email server either accepts or rejects the message. If the email server rejects the email, a bounce message is returned by the ISP to explain why they are unable to deliver the email to the intended address.

How are bounces classified?

When a message is bounced, RelationshipBuilder records the event and reason why the message was returned.  There are four main categories of bounce events.

  • A Soft Bounce occurs when an address is temporarily unable to receive email. An email might incur a soft bounce if the destination mail server is temporarily not responding or a subscriber's mailbox is full. Questline will continue to attempt to send these messages for up to 72 hours until the message is delivered. If a message is continuously deferred for 72 hours, we record these as a single Other Bounce in RelationshipBuilder. Soft bounces themselves are strictly behind the scenes and not documented in RelationshipBuilder.
  • A Hard Bounce occurs when an address is permanently unable to receive email. This typically occurs due to an incorrect email address and either because the mailbox no longer exists or the email address was mistyped.
  • An Other Bounce occurs when an email server rejects the email due to filter issues, such as URL blocks, lack of authentication, or the sending domain or IP address is found on a blacklist.

How are bounces handled?

 If an address hard bounces, RelationshipBuilder automatically adds the address to a Held list and will no longer send to that address. If the address returns a soft bounce, RelationshipBuilder will retry sending until the message expires (typically 72 hours). If the message continues to bounce during that time, then the message expires and a soft bounce event is recorded. A soft bounce does not affect a subscriber's status or suppress them from future mailings. Messages that return an Other Bounce are not added to the Held list and will continue to be sent in the future.

How does managing bounces affect reputation and deliverability?

Bounces can negatively impact your short and long term deliverability. One of the main factors that ISPs monitor to determine your sender reputation and ultimately, the placement of your mail in a customer’s inbox is bounces. Repeatedly sending to invalid email accounts tells ISPs that you are not following proper list management practices and that is a behavior common to spammers. If the number of bounces for an individual ISP exceeds certain levels, you will begin to see message blocking and filtering into the spam or junk folder for even valid customer addresses. That is why it is so important to remove invalid email addresses from your list on an ongoing basis.

How are out of office replies handled?

Out of office replies are not handled by the RelationshipBuilder system as bounces and are simply discarded.