When you send an email, a certain percentage of your distribution list may never receive your message as a result of technical issues on their mail server's end. Pardot keeps track of hard and soft bounces for you and  automatically removes them from your email circulation based on either of the following triggers:

• Immediately upon any hard bounce
• After five soft bounces

Note: the soft bounce threshold is not adjustable. 

Bounce Definitions

• A Soft Bounce is an email that is recognized by the recipient's mail server but is returned to the sender because the recipient's mailbox is full or the mail server is temporarily unavailable. A soft bounce message may be deliverable at another time or may be forwarded manually by the network administrator in charge of redirecting mail on the recipient's domain.
• A Hard Bounce is an email that permanently bounced back to the sender because the address is invalid. A hard bounce might occur because the domain name doesn't exist or because the recipient is unknown.  Some mail servers may hard bounce an email address if the message received is suspected as spam.

What is a good bounce rate?

In business-to-business marketing, anything below 10% is considered a good bounce rate. You can help keep your bounce rate low by keeping your lists clean and adhering to our permission-based marketing policy.

What counts toward bounce rates?

Both soft bounces and hard bounces count toward bounce rate.

What do bounce codes mean?

A bounce message (or code) is a reply from the receiving mail server describing why the email was not delivered. See Bounce Codes FAQ more information and a list of the most common bounce codes.

What happens to a prospect record when an email has five soft bounces or a hard bounce?

• In Pardot, all prospect records with the same email address will be marked Do Not Email. In Salesforce, all records with a matching email address that are syncing from Pardot will be marked Pardot Hard Bounced.
• If a new prospect record is created with an email address that previously bounced, it will automatically be marked as Do Not Email in Pardot, and if the record is syncing to Salesforce, it will be marked Pardot Hard Bounced.
• If the bounce was due to an invalid email address, and it is corrected on a prospect record, it will unmark Do Not Email and Pardot Hard Bounced. If you have several prospect records with the same invalid email address, you will need to update it on each record.
• If you have multiple prospects with the same email address, and one of them bounces, the bounce may appear as an activity on the other prospect records.

An email bounced, but clicks or other activities were recorded after the bounce. Why?

There are a number of reasons why this may happen. The most common reasons are:

• Some spam filters  generate an email view or link click by following links in emails to assess threats.
• Receiving mail server suspected the message was spam and sent a fake bounce message to confuse the spammer, but still delivered the message to the recipient’s spam folder. If the recipient checks the spam folder and opens the email, it looks like the email bounced and was opened later.