What is Soft and Hard Bounce?

When a campaign or email transaction that you send from Taximail is rejected by the subscriber's mail server, it is called "Bounce". There are different bounces depending on the reason you can see from the campaign statistics report and in the Global suppression in your account.

All bounces that Taximail receives is divided into 2 types:

• Soft bounce
• Hard bounce

Soft bounce

A Soft bounce is usually caused by problems that cannot be delivered temporarily while managed differently from the hard bounce.

Below are the reasons for potential soft bounce:

• Body type not supported by a remote host
• Delivery time expired or Network congestion
• Email size exceeded
• Full mailbox
• Invalid DNS MX or A/AAAA resource record
• Limit the amount of email per minute or hour (all recipients)
• Recipient email server is down or offline
• Recipient or recipient's email server rejected the connection
• Recipient or recipient's email server rejected the connection
• Recipient or recipient’s email server has completely blocked delivery
• Recipient's domain MX record point to an empty or loopback address
• Related to content with spam-like characteristics
• SPF/DKIM or DMARC check failed
• Syntax error
• The transaction failed for some unstated reason
• Too many complaints from this sender
• Unable to connect to all relevant MX records
• Undefined MX response
• Wrong protocol version or undefined protocol status

Hard bounce

A Hard bounce is due to the reason that email cannot be sent which the email address that has been returned will be added to Global suppression immediately to prevent future campaigns being sent to this email again.

Below are the reasons for potential hard bounce:

• Domain name does not exist
• Invalid or ambiguous address
• Mailbox disabled, not accepting messages
• Mailbox is over quota permanently or disabled
• Outdated email addresses that have been abandoned
• Permanent error for some unstated reason
• Recipient address not found
• Recipient or recipient’s email server rejected for suspect behavior
• Rejected by private recipient's filters
• Relaying denied or Delivery not authorized
• SPAM complaint
• Undefined network or Routing problem