Bounce management

Bounces are automatically filtered. Contacts with too many bounces, which most often occurs due to invalid/old email addresses, are flagged and won't receive emails after that. This means these contacts don't waste your email credits.

Impact on your account

Bounced emails are undelivered emails sent to inactive or invalid email addresses. High bounce rates can create deliverability issues as too many bounces are an indication of poor list quality or sending unsolicited emails.

Our Terms of Service prohibit sending unsolicited emails.

Hard bounce vs. soft bounce

A hard bounce indicates a permanent reason why an email cannot be delivered, for example:

  • Recipient email address does not exist
  • Domain name does not exist
  • Recipient email server has completely blocked delivery

Soft Bounce

Soft bounces indicate a temporary delivery issue to an email address, for example:

  • Mailbox is full (over quota)
  • Recipient email server is down or offline

New contact records

When contacts are added to the database (via import, API, form submission or manual entry) the email address field is checked for a valid email format. Contacts with an invalid syntax cannot be added to the database.

Bounce reports

You can see a bounce report for email campaigns grouped by "soft" bounces and "hard" bounces and the technical reason for each bounce. 

We keep track of bounced emails and manage these bounces by using fail scores. Three separate fields are maintained for each contact related to email failures:

  1. The Fail Score field keeps track of the severity of failures. Each time a message cannot be sent to a contact their fail score is incremented by 1 - 9 depending on the severity of the fail. For example, a soft bounce or temporary failure increments the fail score by 1 while a hard bounce or permanent failure increments the fail score by 9. The fail score of each contact by default is zero. 
  2. The Send Email field is a yes/no field and it is calculated as a result of the ongoing monitoring of invalid and/or inactive email accounts. It indicates if a contact record has a working email address based on sending history (a combination of bounces and successful deliveries) and determines if we will attempt to send an email to that contact or not. If a contact's fail score is over the Fail Score threshold value of 10 the contact's Send Email flag will change to "No" and the contact will be excluded from future mailings.The fail score and send email fields don't affect contacts' subscription statuses. Subscriptions and bounces are unrelated: someone can be subscribed with an inactive/old email while someone else may be unsubscribed with a vaild email.
  3. The Failures field counts the number of times an email delivery failed and it's always incremented by 1 when an email bounces back.

For example a contact can have 3 failures (3 instances of fail emails), which in turn can result in an overall fail score of 11 (for example 5+5+1). Because the fail score is over the threshold of 10 then this contact's send email field is now set to "No" and will be excluded from future mailings.

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