Bounce Mail Management in Email Studio

Note Where possible, we changed noninclusive terms to align with our company value of Equality. We maintained certain terms to avoid any effect on customer implementations.

As a user, you can’t control bounces, but you can understand how a subscriber acquires a bounced status and the consequences of having too many bounces.

Note This topic describes a typical bounce scenario. Depending on your domain type and account configurations, your experience differs than what is described here. For a customized description of what occurs with your domain, contact your Marketing Cloud Engagement account executive.

Definition

Bounces are messages that ISPs send back to Engagement to explain why they can’t deliver your email. When an email can’t be successfully delivered, the application labels the subscriber as Bounced.

Types of Bounces

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 Engagement. If the email server rejects the email, the subscriber's status changes to Bounced.

Note If a subscriber bounces on an email send and a BCC address interacts with the email, it’s possible for a false bounce to be marked for the subscriber.

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 retries sending the email to the subscriber every 15 minutes for 72 hours, for up to 288 tries. Only after the system stops attempting to retry does a subscriber appear in your tracking as Bounced. When a bounce appears in tracking, it’s official and doesn’t change.

The 288 retries don’t count as bounces. Instead, the full count of unsuccessful retries equates 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 attempts 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 returns their status to Active.

Not every message to a soft-bouncing recipient is retried 288 times. Some bounces can happen immediately and be permanent as it relates to that particular message, but we consider them soft bounces for tracking purposes. Examples of this type of soft bounce that show up faster include these types of ISP responses:

• The mailbox exceeds the maximum allowed storage
• The user account is over its quota
• The mailbox is full
• The mailbox is disabled
• The mailbox is temporarily disabled
• The mailbox is disabled and not accepting messages

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

This table describes the causes of a soft bounce.

Block Bounce

A block bounce occurs when the email server rejects the email because of a lack of authentication, or if the domain or IP address appears on a blocklist. A subscriber who receives a block bounce is retried in the next email send.

This table describes the causes of a block bounce.

Technical Bounce

A technical 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’re retried in the next email send.

This table describes the causes of a technical bounce.

Hard Bounce

A hard bounce occurs when the email server rejects the email due to permanent conditions. This bounce typically results when user unknown or domain not found errors occur. What happens next depends on the subscriber's 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 is retried in your next email campaign. Every email send is considered an email campaign regarding 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 the subscriber bounces in the first or second email campaign, they retain the Bounced status and are retried in your next email campaign. No further attempts are made for this current email campaign.

If 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 is retried in your next campaign. No further attempts are made for this current email campaign. If the bounce occurred more than 15 days before 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 Engagement trusts the ISP or receiver's bounce feedback implicitly. For example, if hotmail.com is a trusted domain and Hotmail's feedback is that an address is bad, the status automatically changes to Undeliverable. They system doesn’t wait for the address to bounce three times over 15 days. If the bounce comes from any other domain, a subscriber receives three bounces to acquire an Undeliverable status. The application doesn’t attempt delivery to this subscriber in any future campaigns.

Current trusted domains include Gmail.com, Hotmail.com (including all active Hotmail country domains like Hotmail.fr), and some smaller regional mailbox providers. If you'd like a copy of all current trusted domains, reach out to mc-deliverability@salesforce.com.

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

This table describes the causes of a hard bounce.

If you have subscribers in a list who continually receive hard bounces, you can remove them from your list.

Unknown Bounce

An unknown bounce occurs when the email server rejects the email and doesn’t provide an identifying error code. An unknown bounce is treated like a soft bounce.

Reactivating Bounced Subscribers

If a subscriber address is in a bounced status but renders images in an email, or if the subscriber clicks a link in an email, their status changes to Active. The bounce count for that subscriber address is set to zero. Imports that specify an Active status automatically resets the bounce count to 0 for any subscriber that is included in the import with an active status.

Bounce Tracking

Engagement tracks your bounces in the tracking area of the email message.

SMTP Bounce Codes

If you run a Bounce Event Extract File, there’s an SMTP Code column that lists a code related to each bounce. View valid values for SMTP reply codes (GreenEnd).

Bounces for Integrated Solutions

Bounces for Engagement integrated products are handled the same way as they are in Engagement. The same rules apply, but sometimes, only the record of a bounce is passed back to the integrated solution. It doesn’t include whether it’s a hard or soft bounce. The system only records the date and time of the event.

Unsubscribed Status

Although unsubscribed subscribers got that status not because of a bounce, in the context of Bounce Mail Management, a subscriber acquires a status of Unsubscribed in these 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 Engagement has a feedback loop (AOL, Hotmail, Comcast, and others)
• The subscriber's address is manually changed to Unsubscribed by a Salesforce Engagement 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. You can use the status field to filter your subscriber searches. Your subscriber workspace uses color-coded icons to indicate subscriber status.

Each subscriber has one of these statuses:

Diagram

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