About bounces
A bounce is an email that is returned to the sender because it was unable to reach the recipient's inbox.
There are two different types of bounces:
Once you send an email, you can immediately start to see bounce information. Identifying bounces and the types of bounces can help provide insights into deliverability problem areas. It is normal to have both hard and soft bounces, but you want to keep your overall bounce rate below 5%. Find out more about tracking bounces.
Hard bounces
A hard bounce is an email that permanently could not be delivered. Some common reasons for hard bounces include an invalid email address or domain name. After Oracle Eloqua finds a hard bounce, it updates the contact's bounce status and marks the email address as invalid. After that, Oracle Eloqua automatically excludes the contact from future email sends.
Typically, hard bounces are returned with an Simple Mail Transfer Protocol (SMTP) code in the 500 range. However, an internet service provider (ISP) might return a hard bounce even if the email address is valid. In these cases, Oracle Eloqua converts the hard bounce to a soft bounce. For example, an ISP might return a hard bounce response with the message Blocked for spam or Too many messages on the server or it may return a reverse DNS lookup failure error. In these cases, the email address is valid, and Oracle Eloqua converts the hard bounce to a soft bounce.
Oracle Eloqua actively manages the logic used to convert hard bounces based on the guideline that the email address is valid. In addition, Oracle Eloqua sometimes converts a soft bounce to a hard bounce. Find out more about that below.
Although Oracle Eloqua does not send emails to hard bounces, you should actively review hard bounce information. Find out more about tracking bounces and best practices below. If you identify contacts that were incorrectly identified as hard bounces, you can manually change the bounce status and set the email address as valid.
Warning: Be sure to verify that an email address is valid before resetting the bounceback status. Continuing to send emails to hard bouncebacks can impact your sender reputation and overall deliverability. Changing the bounceback should always be done with caution.
Soft bounces
A soft bounce is an email that temporarily could not be delivered. This could mean that the email address is valid, but the recipient's inbox was full, the mail server was unavailable, or the email message was too large. These bounces may still be delivered at another time.
Typically, soft bounces are returned with an SMTP reply code in the 400 range. If Oracle Eloqua receives a soft bounce, it will attempt to resend the message for 48 hours in most cases. After that, Oracle Eloqua stops sending the message. The email address remains valid, and you can continue to send messages to this email address.
Sometimes an internet service provider (ISP) might return a hard bounce even if the email address is valid. Oracle Eloqua converts those types of SMTP 500-level failures from hard bounces to soft bounces. For example, failures that are due to reverse DNS lookup failures are converted to a soft bounce.
Oracle Eloqua won't resend messages if the response indicates that the recipient's inbox is full. This response could come with a 4XX or 5XX SMTP reply code but is always treated as a soft bounce. The email address remains valid, and you can continue to send messages to the address.
In certain circumstances, Oracle Eloqua converts a soft bounce to a hard bounce. This happens when Oracle Eloqua receives the soft bounce error 421 4.4.0 [internal] no MXs for this domain could be reached at this time 3 times within 12 months. After receiving this same error for the forth time, Oracle Eloqua assumes the email address is invalid, updates the contact's bounce status, and marks the email address as invalid. After that, Oracle Eloqua automatically excludes the contact from future email sends.
Out of office messages
An out of office message is sent by an autoresponder after delivering the original email. In most cases, out of office messages are not treated as bounces and do not impact a contact's bounce status.
However, if an out of office message is sent to the email’s bounceback address, Oracle Eloqua considers the email as a soft bounce. Whether the out of office message is sent to the email’s from address, reply-to address, or bounceback address depends on how the recipient's email application or server is configured.
For example, Microsoft Outlook sends out of office messages to the from address, and IBM Notes (formerly Lotus Notes) sends them to the reply-to address. If an email client normally sends out of office messages to the reply-to address, but no reply-to address is included in the email, then the out of office message is sent to the from address. There is no way to change the reply behavior of a recipient's email application.
Tracking bounces
It is normal for bounces to occur, but the Oracle Deliverability Operations team recommends the following thresholds:
- Hard bounce rate: 2%
- Overall bounce rate (soft and hard): 5%
- Spam complaints: 0.2%
You can start tracking bounces as soon as your campaign launches using different reports:
- After you launch a campaign, the campaign operational reports provide you with a quick view of email performance over the last 3 months.
- The Bounceback History with Messaging report in Insight shows hard and soft bounces by email address. It provides the email sent, the SMTP error codes and reply codes, and other details about the bounces.
- The Email Bounceback Overview report in Insight shows the total hard, soft, and overall bounces for a given email and date range. This report also allows you to drill through to reports that show more details about the contacts that had a bounce.
- The Spam Unsubscribe report can give you insight into spam complaints.
- The Campaign Analysis Overview and the Email Analysis Overview reports allow you to view the overall bounce rates across multiple campaigns or emails.
Best practices: Bounces
Use the following best practices to help you manage bounces and minimize the impact on your deliverability:
- Regularly review email bounces using the reports available. Unusual spikes in bounces can indicate an issue with your sender reputation.
- If there are a large number of soft bouncebacks from the same domain, the bouncebacks may have been caused by the ISP’s email throttling limits. Read this knowledge base article to find out more.
- Consider segmenting out hard bounces. Although Oracle Eloqua will not send emails to hard bounces, keeping your segments clean can give you more accurate contact counts when you build campaigns.
- If you identify hard bounces outside of Oracle Eloqua, update the impacted contact records as soon as you become are aware of the invalid address.
- Work with your sales team to determine when to delete contacts. It is important to maintain good list hygiene, but you might not always want to delete contacts with hard bounces. For example, maybe a contact changed jobs but is still a valuable contact. Your sales team can follow up with the contact and update the contact details in your CRM, which would then be synced with Oracle Eloqua.
- If you determine that you want to delete contacts, you should first export the contacts and then delete them in a batch.
- While Oracle Eloqua prevents sending emails to contacts with hard bounces, you should make sure that those contacts aren't exported for use by other teams or partners. Again, segmenting out hard bounces is one way to prevent bad contact lists from being exported.
- Review the best practices in other areas and the resources available to you to help with your deliverability.