Hard Bounce

A hard bounce is a failed email delivery due to a permanent issue, such as an invalid or non-existent email address. It cannot be resolved through re-sending.

A hard bounce is an email delivery failure that occurs when an email cannot be delivered to the recipient’s mailbox due to permanent reasons. Unlike a soft bounce, which is a temporary delivery failure, a hard bounce indicates a permanent issue with the recipient’s email address or mail server.

There are several reasons why a hard bounce may occur. One common reason is an invalid or non-existent email address. This can happen when a recipient mistypes their email address, or when an email address is no longer in use or has been deleted. Another reason for a hard bounce is when the recipient’s email server rejects the email due to spam filters or other security measures. This can happen if the sender’s IP address is blacklisted or if the email content triggers spam detection algorithms.

When an email experiences a hard bounce, it is typically returned to the sender with an error message indicating the reason for the failure. This error message can provide valuable information to the sender, allowing them to update their mailing list and remove invalid email addresses.

Hard bounces are important to monitor and manage because they can impact email deliverability and sender reputation. If a sender has a high rate of hard bounces, it can signal poor list hygiene or potential spamming activities, which can lead to being marked as a spammer by email service providers. This can result in future emails being blocked or sent directly to recipients’ spam folders.