Translations:Email bounce tracking system/72/en
From LimeSurvey Manual
The email bounce tracking system will start to look for the survey-id, token-id, and delivery notification which are attached to the email header of each bounced email. If these custom headers exist, the system will change the font color of the wrong email addresses from the survey participants table in red. Also, the email status of the respective entries will be switched from OK to bounced.