What are Hard and Soft Bounces?

When an Email cannot be delivered to a mail server, it is called a bounce.

The Email server usually gives a reason for the incident and uses these reasons to determine how to handle the Email address.

We categorise Bounces into two types: Hard Bounce and Soft Bounce.

Hard Bounce

A Hard Bounce indicates a permanent reason why an Email cannot be delivered.

Here are some common reasons why an Email may bounce.

• The recipient's Email address does not exist.
• The recipient's Email server has permanently blocked delivery.

Soft Bounce

A soft bounce is a temporary failure in email delivery. In most cases, this means that the email address is valid and that the message reached the recipient's server but was rejected.

As a result, the Email was not delivered to the inbox or other folders, such as promotions or spam.

Although there are many reasons why an Email address may bounce, these are some of the most common.

• The mailbox is full (over quota).
• The mailbox is not configured correctly.
• The mailbox is inactive.
• The recipient's Email server is down or offline.
• The recipient's Email server has received too many Emails over a period of time.
• The Email message is too long.
• The domain name does not exist. This may be a temporary problem.
• Email message blocked due to content.
• Email message does not comply with the recipient server's policies.
• Email message failed DMARC.
• Email message does not meet the recipient server's anti-spam requirements.
• The Email message does not meet the recipient server's anti-virus requirements.
• The Email message does not meet the sender requirements of the recipient server.
• The Email cannot be relayed between Email servers.
• The Email cannot be relayed for unknown reasons.

How do we deal with soft bounces?

Before an Email is marked as a soft bounce, it is initially postponed.

We keep trying to resend it for the next 48 hours until it is delivered. If, after these attempts, the Email is still not delivered, we stop trying to send it and it will be marked as a soft bounce in the campaign report.

Where can I see the reason why my Email bounced?

To check the reasons for the bounce, simply click on Campaigns, choose the Campaign you want to check and click on "Activity".

Instead of "All", put "Bounced" and the reasons why each Email bounced will appear (see image).

Are Bounces removed from credits every time they are sent?

Your credits are only used on the first attempt to send the Email.

You will not be charged for resending postponed Emails (before a soft bounce) and we do not attempt to resend Emails that result in a hard bounce.

Updated on: 08/07/2025