Bounce interpretation

Bounces are addresses that return a message. The message is a notification sent by the system, which indicates that the recipient is unavailable.

If we receive three consequent hard bounces from the address, and the time between each bounce is equal to or more than seven days, the address is deactivated. However, this policy might be applied more strictly for some email providers.

Delivering newsletters to malfunctioning addresses negatively affects sender reputation. The purpose of the practice is to improve our customers’ message deliverability.

Bounces can be viewed from the Reports General Details page under the Bounces row by clicking View.

The subscriber has already received the message
Delivery to multiple lists. The message has already been sent to the address from another list. No further action required.

Invalid domain
An unknown domain, such as company.com. The address is probably invalid.

Unknown recipient
Unknown recipient, such as firstname.lastname@. The address is probably invalid.

Full mailbox
The Recipient's mailbox is full. The address exists, but the subscriber cannot receive messages temporarily.

Out of office
The address is valid, the return mail was probably sent by a vacation auto-reply. No further action required.

Unidentified
The return mail could not be automatically recognized. Recurring notifications generally imply an invalid address.

Unknown
The reason for the bounce is unknown. Recurring notifications generally imply an invalid address.

Spam
The receiving server identified the newsletter as spam.

Deleted after bounce
The system has detected that the address is malfunctioning.

Extra-unsubscription
The subscriber has unsubscribed the newsletter.

Greylisted
Domain has probably turned invalid. The address might be misspelled, for example, "gmail.con" or the domain has expired.

Extra-message-too-large
The receiver thinks the email too large to receive. 

Abuse
The receiving server refused to accept the email based on abuse, possibly because the message was identified as spam.

Recipient on removal list
The recipient on the removal list is not an actual inactive address but means a recipient who has been blocked by the sender of the letter when sending the message. Recipients can be blocked one list at a time in particular delivery, or it can be specified that, for example, recipients sent within a week will not receive that letter at all.

If an address returns messages many times during a certain time period, the system removes the address as invalid. Only invalid addresses will be removed, the system carefully checks that no valid addresses are removed.

Addresses removed as invalid can be viewed from the Subscriber tab, by choosing Unreachable subscribers from the drop-down list. The system notifies about invalid addresses when lists are uploaded onto the system.