Purpose 

The purpose of this document is to explain how email bounces are handled within the ExactTarget application. As a user, you cannot control anything having to do with bounces, but rather you can understand how a subscriber acquires a bounced status and the consequences of having too many bounces.

Note: This document describes the typical bounce scenario, but depending on your domain type, you may not experience what is described here. For a customized description of what occurs with your domain, contact your ExactTarget representative.

Definition

Bounces are messages that ISPs send back to ExactTarget to explain why they can't deliver your email to the email address you sent it to. When an email cannot be successfully delivered, the application labels the subscriber as Bounced.

Explanation

The subscriber's email server either accepts or bounces an email when it's sent. If the email server accepts the email, the subscriber's status remains Active in the ExactTarget application. If the email server rejects the email, the subscriber's status changes to Bounced.

Here's how it works:

Soft Bounce

A soft bounce occurs when the email server rejects the email due to a seemingly temporary condition, such as a full inbox. When that happens, the system will retry sending the email to the subscriber every 15 minutes for 72 hours, which totals 288 tries. Only after the system attempts the 288 tries does a bounce appear in your tracking as bounced. Once a bounce appears in tracking, it is official and will not change.

The 288 re-tries do not count as bounces, instead 288 unsuccessful retries equate to one soft bounce. If the system attempts delivery 288 times and the message bounces each time, the subscriber's status is set to Bounced. If the email is delivered during the 288 tries and the subscriber opens the email, the subscriber's status is set to Active. Also, a Bounced subscriber can find an old email from you in their inbox and open it, which will return their status to Active.

After ExactTarget receives the third soft bounce for a subscriber, their status is set to Held.

The following table describes the causes of a soft bounce.

CauseDefinitionPossible Cautions and Resolutions
Inactive Account Address is temporarily unavailable as recipient's mailbox is inactive or temporarily disabled The subscriber's email account is temporarily inactive or disabled. Mailboxes can be disabled for several reasons, including infrequent use, change of address, delinquency or dispute. These errors could be temporary or permanent. Recommended actions include sending messages to these subscribers in the short term to monitor acceptance, and then to contact the subscriber through other methods to confirm address, if delivery issues persist.
Mailbox Full Recipient's mailbox is full or has exceeded storage allocation Your recipient's mailbox is full or it has exceeded it's storage allocation. The could be caused by infrequent use, a temporary change in email checking habits, or an address change. Mailbox full errors should serve as a warning sign. Consider contacting the subscriber through alternative means to confirm that you are mailing to a valid and frequently checked address.
Temporary Domain Failure Temporary failure at the receiving domain The subscriber's mailbox is not currently accepting messages. This is a temporary deliverability issue that should be resolved prior to future sends. Continue to monitor deliverability for this subscriber. Consider contacting this subscriber through alternative means if these deliverability issues persist.
Other Mailbox temporarily unavailable or indecipherable bounce message received The subscriber's mailbox is not currently accepting messages. This is a temporary deliverability issue that should be resolved prior to future sends. Continue to monitor deliverability for this subscriber. Consider contacting this subscriber through alternative means if these deliverability issues persist.

Block Bounce

A block bounce (which is considered a type of soft bounce) occurs when the email server rejects the email due to filter issues, such as URL blocks, lack of proper authentication, or the domain or IP address is found on a blacklist utilized by the receiving domain. A subscriber who receives a block bounce will be re-tried in the next email send.

The following table describes the causes of a block bounce.

Cause

Definition
Complaint Your email is blocked due to complaints
Blacklist IP address is on a blacklist
Content Message was filtered due to content
URL Block Emails containing your URLs are blocked
Authentication Message lacks required authentication

Technical Bounce

A technical bounce (which is considered a type of soft bounce) occurs when the email server rejects the email due to technical errors, such as a data format or network error. When a subscriber experiences a technical bounce they will be re-tried in the next email send.

The following table describes the causes of a technical bounce.

CauseDefinition
Server Too Busy Receiving email server is temporarily overwhelmed with delivery attempts from you and other senders
Data Format Error Email is rejected due to formatting or line length errors
Network Error Connection lost or timed our during delivery line length errors
 

Hard Bounce

A hard bounce occurs when the email server rejects the email due to permanent conditions (this typically results when "user unknown" or "domain not found" errors occur). What happens next depends on the subscriber's current status. If the subscriber's status was already Active, their status now changes to Bounced. No more attempts are made to send this email campaign to this subscriber, and the subscriber will be re-tried in your next email campaign. Every email send is considered an email campaign with respect to bounce handling.

If the subscriber's status was already Bounced, which indicates they had experienced a bounce previously, the application treats the bounce differently. If this email campaign is the first or second email campaign in which the subscriber bounced, the subscriber retains the Bounced status and will be re-tried in your next email campaign. No further attempts are made for this current email campaign.

If, however, this email campaign is the third campaign in which the subscriber bounced, the application checks when the first bounce message was received for this subscriber. If fewer than 15 days have passed since the first bounce message was received, the subscriber retains the Bounced status and will be re-tried in your next campaign. No further attempts are made for this current email campaign. If the bounce occurred more than 15 days prior to the first bounce message , the subscriber status changes to Undeliverable unless the bounce is from a trusted domain. A trusted domain is one in which ExactTarget trusts the ISP or receiver's bounce feedback implicitily. For example. if hotmail.com is a trusted domain, we trust Hotmail's feedback that an address is bad, and therefore we'll change the status of a hard bounced hotmail.com address to Undeliverable immediately instead of waiting for the address to bounce three times over 15 days. If the bounce comes from any other domain, a subscriber must receive three bounces to acquire an Undeliverable status. The application will not attempt delivery to this subscriber in any future campaigns. 

Current trusted domains are Gmail.com, Hotmail.com (including all active Hotmail country domains like Hotmail.fr), and all active Road Runner domains like nyc.rr.com.  Check back here periodically as we update trusted domains as needed from time to time.

While this model suits most cases, certain ISPs change from time-to-time based on how they handle spam and a number of other deliverability items. 

The following table describes the causes of a hard bounce.

CauseDefinitionPossible Cautions and Resolutions
Domain Unknown Domain is bad or non-existent Sending to unknown domains is a result of poor data capture methods, old data, or questionable data sources. Sending to old lists can also increase the likelihood of mailing to dead domains, as domains that are no longer active will be represented on old lists. To avoid receiving a high number of "Domain Unknown" errors, we recommend sending a test send to 10% of your regular mailing volume. In doing so, you can assess the results from the test send without exceeding the acceptable bounce and complain rates and make a reasonable risk assessment before proceeding with a larger send.
User Unknown Address is invalid and/or failure is permanent per bounce message Industry statistics indicate that up to 33% of email addresses become invalid over a 12 month period. Receiving the User Unknown error indicates that the address is no longer active or has never been an active email address. Because of the high rate of turnover of email addresses, sending to subscribers on a regular basis will decrease the possibility of a sudden spike on a specific campaign. If mailing to an old subscriber list, we recommend sending a random 10% test to avoid a sudden increase in bounces. This error could also be the result of poor data capture methods. If this is the case, we recommend requiring subscribers to enter their email address twice
Bad Address Syntax Email address invalid

The email is not in a correct syntax. For example, you may have left out the "@" symbol or didn't include a domain name (like "examplecom" instead of "example.com"). 

Check your email address syntax and correct any errors you see. 

High Unknown Address Percentage Email is blocked due to the high quantity/percentage of unknown or inactive addresses on your list The subscriber's ISP has flagged your IP address for sending too many messages that got blocked. The ISP sees that you sent emails to people that didn't accept them. To improve this, see the section on Best Practices.
Other Address is invalid and/or failure is permanent per bounce message

 

 

If you have subscribers in a list who continually receive hard bounces you may want to think about removing them from your list. See Removing Subscribers with Hard Bounces From Your Subscriber List.

Reactivating Bounced Subscribers

If a subscriber whose address is in a bounced status renders images in an email, or if the subscriber clicks on a link in an email, the status of their address will be changed back to Active and the bounce count for that subscriber address will be set back to zero.  

Bounce Tracking

ExactTarget tracks your bounces in the tracking area of the application. To access the tracking data, follow these steps:

  1. Click the Tracking tab. 
  2. Click my tracking
  3. Click on the job for which you wish to view tracking.
  4. View the Send Performance area.
    /Global/Documentation/6755/SendPerformance.png

SMTP Bounce Codes

If you run a Bounce Event Extract File, there is an SMTP Code column that lists a code related to each bounce. Valid values available at this location: http://www.greenend.org.uk/rjk/2000/05/21/smtp-replies.html

How ExactTarget Handles Bounces

As part of ExactTarget's Deliverability Report Card Service, if 20% or more of the email you send during a week (Monday through Sunday) bounces, you'll receive an Account Warning notice from Deliverability Services. If 40% or more of the email you send during a week bounces, you'll receive an Account Hold notice from Deliverability Services and be required to speak with a Deliverability Consultant before the account hold is lifted. 

ExactTarget takes bounces very seriously. Poor deliverability from any of our customers damages the reputation of the company and, by extension, all of our customers. Therefore, ExactTarget's Sending Guidelines and Thresholds are in place to prevent abuse of our email system and to ensure our clients practice permission-based, opt-in email. We continue to lead the industry in deliverability rates - due in part to our commitment to, enforcement of, and client consultation on permission marketing best practices.

Bounces for Integrated Solutions

Bounces for ExactTarget's integrated solution, such as Salesforce, are handled the same way as they are in ExactTarget. The same rules apply, but often, only the record of a bounce is passed back to the integrated solution. For example, with Salesforce, the bounce record is passed to Salesforce but you can't tell if it's a hard or soft bounce. The system only records the date and time of the event. 

For more information, see our AppExchange Tracking documentation.

Unsubscribed Status

Although subscriber addresses that have a status of Unsubscribed came to be in that state not because of a bounce, it's worth noting here in the context of Bounce Mail Management that a subscriber address will acquire a status of Unsubscribed in the following ways:

  • The subscriber clicks an unsubscribe link in an email or chooses to be unsubscribed in a profile center
  • The subscriber reports an email as spam to an ISP with which ExactTarget has a feedback loop (AOL, Hotmail, Comcast, and others)
  • The subscriber's address is manually changed to unsubscribed by an ExactTarget user

Subscriber Status

 

 

A subscriber's email status is one of the fields that you can include when you export individual subscriber data or export an entire subscriber list and is also a field that you can use to filter your subscriber searches. Your subscriber workspace uses color-coded icons to indicate subscriber status.

Each subscriber has one of the following statuses:

Color CodeStatusExplanation

/Global/Documentation/6755/green.png (green)

Active

A subscriber who meets either of the following criteria has a status of Active:

  • No activities have occurred to make the subscriber's status Bounced, Undeliverable, Unsubscribed, or Deleted.
  • A subscriber whose status was Bounced or Undeliverable is recorded as having opened or clicked through a received email. In this case, the system changes the subscriber's status back to Active.

/Global/Documentation/6755/yellow.png (yellow)

Bounced
(Returned)

 

 

A subscriber who meets the following criteria has a status of Bounced:

  • one or two soft bounces are received for the subscriber
  • one hard bounce is received for the subscriber

/Global/Documentation/6755/gray.png (gray)

Held (Undeliverable)

A subscriber who meets the following criteria has a status of Held (Undeliverable):

  • Three hard bounces or three soft bounces are received for the subscriber and at least 15 days have passed since the first bounce.

    If the bounce was from a trusted domain, only one hard bounce is required. Current trusted domains are Gmail.com, Hotmail.com (including all active Hotmail country domains like Hotmail.fr), and all active Road Runner domains like nyc.rr.com.  Check back here periodically as we update trusted domains as needed from time to time.

/Global/Documentation/6755/red.png (red)

Unsubscribed

A subscriber who meets any of the following criteria has a status of Unsubscribed:

  • The subscriber has requested to be removed from a single list, multiple lists, or all lists. In these cases, the subscriber's status is changed to Unsubscribed for the selected list(s) or at the All Subscribers level.
  • A user manually unsubscribes a subscriber, thus changing the status to Unsubscribed for the list at which the action was taken.
  • The subscriber has submitted a spam complaint in the user interface of any ISP or webmail service that provides a feedback loop (FBL) to ET. In this case, the subscriber's status is changed to Unsubscribed at the All Subscribers level. ISPs that offer feedback loops include AOL, Hotmail, Comcast, Roadrunner, Synacor, Cox Cable, Excite/BlueTie, Mailtrust, IBM/Outblaze, Tucows/OpenSRS, Juno, USA.net and Yahoo (if a client is properly utilizing Sender Authentication Package). Others may also be included.
  Deleted

A subscriber who meets either of the following criteria has a status of Deleted:

  • A user has deleted a subscriber from a list other than the All Subscribers list. In this case, the subscriber's status for that list only is Deleted.
  • A user has deleted a subscriber from the All Subscribers list. In this case, the subscriber's global status is Deleted.

Diagram

The diagram below illustrates the bounce process, showing how a subscriber address status changes from active, to bounced, to undeliverable.

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Last updated by jcloud at 13:18, 8 Jul 2014