What are bounces?

Bounces are emails that were unable to be delivered for some reason.

After a campaign has been sent, there are 3 possible outcomes in terms of bounces:

  1. If the email is successfully delivered to a recipient, no bounce is recorded.
  2. If we receive a bounceback message from the recipient's mail server, either a hard bounce or soft bounce (see below) is recorded for that recipient depending on the specific bounceback message we received.
  3. If we are unable to successfully deliver the email to the recipient's mail server and do not receive a bounceback message, we will continue trying to deliver the email for up to 48 hours. If after 48 hours, we have still not been able to deliver the email to the recipient's mail server, then it will be classified as a soft bounce.

There are two kinds of bounces: hard bounces and soft bounces. 

Hard bounces were permanently bounced back by the recipients' mail server because of one of the following reasons:

  • Invalid address
  • Inactive address
  • User not found
  • Invalid domain
  • Reason not determined
  • Unknown

Email addresses that hard bounce are recorded as a Hard Bounce in the Reports area for the specific campaign.

These contacts are also classified as "bounced" within the Contacts area of the system, which means you will not be able to send campaigns to them again until their email address is edited or their delivery status is reset.

Soft bounces were recognized by the recipients' mail server but bounced back to us because of one of the following temporary reasons:

  • Account inactive
  • Mailbox full
  • Server offline
  • Routing problem
  • Flagged as spam
  • Relay problem
  • Inbound quota exceeded
  • Authentication required
  • Reason not determined

These contacts are NOT classified as "bounced" within the Contacts area of the system, which means you can continue to send campaigns to them.

However after an email address has soft bounced 15 times, it will be classified as a "bounced" within the Contacts area of the system which will prevent you from continuing to send to the email address. This is done by design as a protection against sending to potential spam traps.