Soft bounce

A soft bounce indicates a delivery problem, where the email could not be delivered to the recipient’s mail server due to a temporary problem (it is not a definitive error).

Soft bounces are generated due to a temporary problem, so once the problem has been solved, the recipient will be able to receive the email normally and quickly.

Each email marketing provider manages soft bounces in a particular way, but always based on the SMTP response of the destination server. It is common that if the email address continues to return the soft bounce status after several email marketing campaigns in a row, it is considered as a hard bounce (definitive bounce).

1. Hard bounce and soft bounce

Hard bounces are bounces that will be generated when the message can’t be delivered due to a definitive and permanent problem with the email address to which the email was sent. These addresses can no longer be sent to.

Whereas, soft bounces are generated when the email can’t be delivered due to a temporary and not permanent problem with the email address to which you want to deliver the message. You can try to send more messages to those email addresses in the future.

2. Reasons for a soft bounce

Although the most common reason for a soft bounce is that the recipient’s mailbox is full, there are many different reasons for our email to end up marked as a soft bounce. Some of the most common reasons that will generate a soft bounces are:

• The recipient’s mailbox is full, it has exceeded its allotted space quota.
• The destination mailbox is inactive or doesn’t exist on the server.
• The recipient’s mailbox is not configured correctly.
• The domain name doesn’t exist (the recipient’s domain).
• The recipient’s mail server is down/not connected.
• The recipient’s email server has received too many emails for a period of time (time set by the server administrator).
• The email message is too large (due to attachments).
• The email message doesn’t comply with the anti-spam policies of the destination server.
• The email message doesn’t comply with the DMARC authentication requirements of the destination server.
• The email message was blocked because of its content (destination server’s policies).