Bounces explained

Bounce definition

A bounce occurs when an email cannot be delivered to the intended email address. The respective mail server sends our system an error message indicating that the email could not be delivered. This feedback is called bounce. Bounces are divided into soft bounces and hard bounces.

  • A soft bounce occurs when an email cannot be delivered due to a temporary issue. This can happen e.g. if the recipient’s mailbox is full or the receiving server has been swamped by incoming emails.
  • A hard bounce occurs when an email cannot be delivered because the email address no longer exists or the receiving mail server is blocking emails.

If a recipient is sent an email and his address produces a bounce the system will automatically block this address for a certain period of time. The exact duration of this block depends on the type of bounce:

Bounce type Block after Duration of block
Soft bounce 3 attempts 1 month
Hard bounce 1 attempt 1 year

The addresses will automatically be unblocked after the time of the block is up.

Checking bounces in reports

The affected bounce addresses can be found two ways. You can find all bounces that have occurred in a specific email campaign. To do this just open the respective report (through [Reports]) and click on [Bounces] within the overview.

After these steps you will get an overview of all affected addresses. If needed you can export these contacts by clicking [Action] > [CSV]. If you would like to check the detail information on the bounces you can select . You will find an overview of bounce details here.

Checking bounces in recipient groups

Alternatively you can also check bounces based on recipient groups. Open the recipient group via [Recipients] and set the filter to [Bounces].

This category contains all addresses that have either produced 3 soft bounces or 1 hard bounce. These addresses are added to the global bounce index and are marked blue for a better overview. After the respective block has ended the addresses are activated again. If you do not want this to happen you can of course remove or deactivate the bounces. You will find information on how to do this here.

Important notes:

  1. You cannot compare numbers from the bounce overview of an individual email and the bounces from within a recipient group. The bounces in the report have exclusively occurred in that particular email, the bounces within the recipient group have occurred across emails.
  2. Bounces are administered globally. This means that recipients might be marked as bounces within your system even though you have not yet sent them an email. Our system already knows these particular addresses and knows that they have been emailed to unsuccessfully multiple times.
  3. You cannot reactivate bounces.
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