Resolve Soft Bounce / Hard Bounce errors

This guide explains how to handle Soft Bounce and Hard Bounce errors that can occur during email sending, particularly when using Infomaniak Newsletter.

Hard Bounce

A hard bounce is an email that cannot be delivered due to permanent reasons.

• Email sent to a non-existent address
• Email domain of the recipient that is not a real domain
• Recipient's server that does not accept emails
• Etc.

Example from the Infomaniak Newsletter tool after sending with 20% Hard Bounce:

Soft Bounce

A soft bounce is an error message indicating that the email is not delivered to its recipient and is related to a temporary delivery issue: the email address is valid, and the sender can retry sending.

Several reasons can explain a soft bounce where the recipient's server temporarily refuses the email:

• The recipient's inbox is full: due to insufficient storage capacity, the recipient no longer receives messages
• An issue occurs with the recipient's mail server: the server is temporarily unavailable or down, or the user has inadvertently set up filters that prevent receiving certain messages
• When the email content, especially its attachments, is too large, the delivery issue occurs during sending

Unless the recipient has permanently abandoned their inbox without deleting their account, the soft bounce is a temporary issue.