About Bounces

After a bounce occurs for a recipient email address, Mandrill stops attempting delivery of the email. Further email to that address will be rejected temporarily.

Mandrill utilizes a set of heuristics to determine whether a bounce should be classified as a soft or hard bounce. Permanent errors such as invalid mailboxes will get classified as hard bounces, while quota errors and other temporary problems are treated as soft bounces. Hard bounce rejections last longer than soft bounce rejections, and Mandrill doesn't automatically convert soft bounces to hard bounces. If you're seeing a lot of soft bounces to an address, it may be a sign that the address is unusable.

View the Rejection Blacklist

  1. Go to the Settings page in your Mandrill account.
  2. Select Rejection Blacklist to view a list of addresses that have been added to the rejection list.

You can also view the Rejection Blacklist for a subaccount.

In addition to the email address, you'll see the following items:

  • The reason the email address was added to the blacklist
  • Which sender the rejection applies to
  • The date the rejection expires

After the rejection expires, the email address remains on the list for reference, but email sent to that address will be attempted again instead of being rejected.

Rejections shouldn't be removed in bulk, but if you know that a bounce was temporary or you've resolved an issue with the receiving server, you can remove individual rejections for a small hit to your account's reputation.