Adobe Campaign Standard
In some scenarios, the customer delivery summary report may show that fewer emails have been delivered than opened. This can be confusing and cause concern for users. However, this issue can be easily explained.
Note: Please note that we incorrectly flip the status of a message to “Failed” when an inbound email is processed for it (in this case a spam complaint). That message was in fact delivered, so the status should be ‘Sent’ and counted as a delivered email, but this does not happen. In this scenario, Adobe Campaign is incorrectly resetting the status to ‘Failed’. This is scheduled to be fixed in ACS.
Suppose a mail was sent, and the recipient opened the email, clicked on a link, and then marked it as SPAM. In such a scenario, the feedback loop will make the delivery count zero. This means that the number of delivered emails will be counted as zero (broad logs), whereas the number of unique clicks will be more than zero (tracking logs). As a result, the report will show fewer emails delivered than opened.