Email bounce management

Bounce management is important for maintaining a strong deliverability and sender reputation and ensuring your emails reach the correct recipients. Without effective bounce management, your messages may end up in spam folders or not be delivered at all, damaging your brand’s credibility and reducing engagement.

What is an email bounce?

An email bounce occurs when an email fails to reach a recipient's inbox. Common reasons include:

• Invalid email address
• Full mailbox
• Temporary server issue

When an email bounces, the recipient’s mail server (for example, Gmail, Outlook) sends an automatic response explaining the delivery failure. This response includes the bounce reason, date, and time. The main categorization, soft or hard bounce, comes from the providers. However, Bloomreach Engagement takes extra steps to reduce the risk of bounces on your long-term reputation.

Bounce types and actions

Bloomreach Engagement supports the following bounce types:

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Important

Bloomreach Engagement doesn’t get spam complaint data from Gmail. Use Google Postmaster Tools to monitor complaints from Gmail users.

How cumulative bounces work

Cumulative bounces track repeated soft bounces (cumulative=true) for the same email address. If an address bounces multiple times, it’s automatically suppressed to prevent further delivery attempts. This helps protect the sender's reputation and improves deliverability.

Suppression logic

1. Temporary suppression: Triggered after 3 consecutive soft bounces. The email address is suppressed for 14 days.
   1. Effect: No emails are sent during suppression.
   2. Tracking: Campaign event records status="suppressed" with message: "Temporarily suppressed due to repeated soft bounces for this email address".
   3. Expiration: Suppression expires after the defined period (valid_until=timestamp).

2. Permanent suppression: If the email address continues to bounce after 2 temporary suppressions, it’s permanently suppressed and invalidated.
   1. Effect: The system prevents further email attempts to this address.
   2. Tracking: The contact is invalidated, tracking invalid_contact event with the reason="Permanently suppressed due to repeated soft bounces for this email address”.

Suppression flow

1. First temporary suppression: 3 consecutive soft bounces → 14-day suppression
2. Second temporary suppression: Another 3 consecutive soft bounces after suppression lifts → 14-day suppression.
3. Permanent suppression: If another soft bounce occurs after the second temporary suppression, the email address is permanently suppressed.

If an email campaign is sent during a temporary suppression period, it’s blocked. After suppression expires, it sends normally.

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Note

Consecutive soft bounces mean no successful deliveries (delivered/revalidated campaign events) between bounces (cumulative=true). Suppression applies at the next campaign send attempt.

Exceptions

Cumulative logic won’t apply if the email property doesn't match the recipient in the soft bounce events counted in the cumulative bounce. For example, when the email property was updated.

Cumulative bounce settings

You can customize the number of soft bounces required for temporary suppression and its duration within Project settings.

To view current bounce settings:

1. Go to Project settings.

   

2. Under Campaigns > Channels, select Emails.

3. Go to Email suppression > Bounce management.

4. Review the parameters.

Bounce management parameters

• Number of soft bounces before suppression: The default is 3 for optimal results. However, if you see a pattern in your bounce data, consult your consultant or email specialist about changing this parameter.
• Temporary suppression duration: The default is 14 days (min 1, max 180). Adjust this period based on your sending frequency.

Invalidate contacts

When an email permanently bounces (hard bounce, preblocked, or cumulative bounce), Bloomreach Engagement automatically invalidates the contact to prevent future emails.

When invalidation occurs, 2 actions happen:

1. Set the customer attribute email_invalid to true:
   1. This action ensures the profile is excluded from all future email campaigns.
2. Track the invalid_contact event:
   1. This event logs when the invalidation happened and the reason for it. The following details are logged in the event:
      1. channel: How the invalidation was identified.
      2. contact_info: The affected email address.
      3. reason: Why the email was marked invalid.
      4. source: Where the bounce originated (Bloomreach Engagement, ESP).

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Important

Setting the email_invalid flag doesn't affect transactional emails. These are always attempted, regardless of suppression rules.

Reengage permanently bounced profiles

If a permanently suppressed contact is valid, you can reinstate it using these methods.

1. Update the email_invalid attribute to false.
2. Track a revalidated campaign event with status=revalidated.

Required campaign event structure

• Status: revalidated (mandatory)
• Recipient: The email address associated with the bounces (mandatory).
  • It should match the profile's current email attribute.
• Message: Custom message containing the reason for revalidation (optional).

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Warning

Re-enabling permanently bounced profiles can harm your domain reputation. Use caution before proceeding.

Best practices for bounce management

To improve email deliverability and reduce bounces:

• Regularly clean your email list to remove invalid or inactive addresses. Invalid email addresses are one of the primary causes of bounces.
• Look for patterns in your bounce data to uncover recurring issues, such as soft bounces from a particular domain or consistent hard bounces from invalid addresses.
• Check your reports to find specific issues with your email campaigns. For example, analyze the bounce reasons to identify problems with email content or technical configurations.
• After addressing any issues (for example, fixing invalid email addresses), revalidate contacts to ensure they are eligible for future campaigns.

Manage bounces proactively to protect your sender reputation, improve engagement, and maintain high deliverability rates.

Email bounce report

To learn how to create a bounce report, watch the video.

Deliverability investigation dashboard

To gain insights into metrics such as the delivery rate or hard bounce rate, use the Email deliverability dashboard.

1. Go to Overview > My dashboards.
2. Click Create new dashoard.
3. From the predefined dashboards, select the [Email] Deliverability Investigation.

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