Understanding delivery failures understanding-delivery-failures

About delivery failures about-delivery-failures

When a delivery cannot be sent to a profile, the remote server automatically sends an error message, which is picked up by the Adobe Campaign platform and qualified to determine whether or not the email address or phone number should be quarantined. See Bounce mail qualification.

Email error messages (or “bounces”) are qualified by the Enhanced MTA (synchronous bounces) or by the inMail process (asynchronous bounces).
SMS error messages (or “SR” for “Status Report”) are qualified by the MTA process.

Messages can also be excluded during the delivery preparation if an address is quarantined or if a profile is on the denylist. Excluded messages are listed in the Exclusion logs tab of the delivery dashboard (see this section).

Related topics:

Identifying delivery failures for a message identifying-delivery-failures-for-a-message

Once a delivery is sent, the Sending logs tab (see this section) allows you to view the delivery status for each profile and the associated failure type and reason (see Delivery failure types and reasons).

A dedicated out-of-the-box report is also available. This report details the overall hard and soft errors encountered during deliveries as well as the automatic processing of bounces. For more on this, refer to this section.

Delivery failure types and reasons delivery-failure-types-and-reasons

There are three types of errors when a delivery fails:

  • Hard: A “hard” error indicates an invalid address. This involves an error message that explicitly states that the address is invalid, such as: “Unknown user”.
  • Soft: This might be a temporary error, or one that could not be categorized, such as: “Invalid domain” or “Mailbox full”.
  • Ignored: This is an error that is known to be temporary, such as “Out of office”, or a technical error, for example if the sender type is “postmaster”.

The possible reasons for a delivery failure are:

Error label
Error type
User unknown
The address does not exist. No further deliveries will be attempted for this profile.
Quarantined address
The address was placed in quarantine.
An error has occurred in the message delivery chain (such as domain temporarily unreachable). According to the error returned by the provider, the address will be sent to quarantine directly or the delivery will be tried again until Campaign receives an error which justifies the Quarantine status or until the number of errors reaches 5.
Address empty
The address is not defined.
Mailbox full
The mailbox of this user is full and cannot accept more messages. This address can be removed from the quarantine list to make another attempt. It is removed automatically after 30 days. In order for the address to be automatically removed from the list of quarantined addresses, the Database cleanup technical workflow must be started.
The address has been placed in quarantine due to a security feedback as a spam report. According to the error returned by the provider, the address will be sent to quarantine directly or the delivery will be tried again until Campaign receives an error which justifies the Quarantine status or until the number of errors reaches 5.
The address has already been detected in the segmentation.
Not defined
the address is in qualification because errors have not been incremented.
Error ignored
The address is on allowlist and an email will be sent to it in any case.
Address on denylist
The address was added to the denylist at the time of sending.
Account disabled
When the Internet Access Provider (IAP) detects a lengthy period of inactivity, it can close the user’s account: deliveries to the user’s address will then be impossible. The Soft or Hard type depends upon the type of error received: if the account is temporarily disabled due to six months of inactivity and can still be activated, the status Erroneous will be assigned and the delivery will be tried again. If the error received signals that the account is permanently deactivated then it will directly be sent to Quarantine.
Not connected
The profile’s mobile phone is switched off or not connected to the network when the message is sent.
Invalid domain
The domain of the email address is incorrect or no longer exists. This profile will be targeted again until the error count reaches 5. After this, the record will be set to Quarantine status and no retry will follow.
Text too long
The number of characters in the SMS message exceeds the limit. For more on this, see SMS encoding, length and transliteration.
Character not supported by encoding
The SMS message contains one or more characters that are not supported by the encoding. &For more on this, see Table of characters - GSM Standard.

Related topics:

Retries after a delivery temporary failure retries-after-a-delivery-temporary-failure

If a message fails due to a temporary error, retries will be performed during the delivery duration. For more on the types of errors, see Delivery failure types and reasons.

The number of retries (how many retries should be performed the day after the send is started) and the minimum delay between retries are now based on how well an IP is performing both historically and currently at a given domain. The Retries settings in Campaign are ignored.

To modify the duration of a delivery, go to the advanced parameters of the delivery or delivery template, and edit the Delivery duration field of the Validity period section.

The Delivery duration parameter in your Campaign deliveries is now only used if set to 3.5 days or less. If you define a value higher than 3.5 days, it will not be taken into account.

For example, if you want retries for a delivery to stop after one day, you can set the delivery duration to 1d, and the messages in the retry queue will be removed after one day.

Once a message has been in the retry queue for a maximum of 3.5 days and has failed to deliver, it will time out and its status will be updated to Failed in the delivery logs.

Synchronous and asynchronous errors synchronous-and-asynchronous-errors

A delivery can fail immediately (synchronous error), or later on, after it has been sent (asynchronous error).

  • Synchronous error: the remote server contacted by the Adobe Campaign delivery server immediately returned an error message, the delivery is not allowed to be sent to the profile’s server.
  • Asynchronous error: a bounce mail or a SR was resent later by the receiving server. Asynchronous errors can occur up until one week after a delivery has been sent.

Bounce mail qualification bounce-mail-qualification

For synchronous delivery failure error messages, the Adobe Campaign Enhanced MTA (Message Transfer Agent) determines the bounce type and qualification, and sends back that information to Campaign.

The bounce qualifications in the Campaign Message qualification table are no longer used.

Asynchronous bounces are still qualified by the inMail process through the Inbound email rules. To access these rules, click the Adobe logo, at the top-left, then select Administration > Channels > Email > Email processing rules and select Bounce mails. For more on this rule, see this section.

For more on bounces and the different kinds of bounces, see this section.

Optimizing email deliverability with double opt-in mechanism optimizing-mail-deliverability-with-double-opt-in-mechanism

Double opt-in mechanism is a best practice when sending emails. It protects the platform from wrong or invalid email addresses, spambots, and prevents possible spam complaints.

The principle is to send an email to confirm the visitor’s agreement before storing them as ‘profiles’ into your Campaign database: the visitor fills out an online landing page, then receives an email and has to click in the confirmation link to finalize its subscription.

For more on this, see this section.