Bounce
This event webhook is called whenever one of your emails bounces. Emails bounce for various reasons.
List of Body Attributes
This table shows the list of parameters present in the payload and their explanations.
| Parameters | Data Type | Description |
| webhook_name | String | Name of the webhook you configured. |
| webhook_id | String | ID of the configured webhook. |
| action | String | Name of the event. |
| actionType | String | Type of bounce, which can be hard bounce or soft bounce. |
| data | JSON Array | An array of data about the events |
| bounce_code | String | The bounce code provided by the recipient email service provider. |
| bounce_type | String | Type of bounce, which can be hard bounce or soft bounce. |
| bounce_extended_code | String | An additional code that indicates a specific case of bounce. This is also returned by the recipient email service provider. |
| bounce_reason | String | Reason for the bounce. |
| action_time | Long | Time at which the bounce event happened. |
| sending_ip | String | The IP through which the mail was attempted, but was bounced. |
| contact_id | Long | ID of the contact to which the mail was attempted, but was bounced. |
| contact_email | String | Email address of the contact to which the mail was attempted, but was bounced. |
| rcpt_domain | String | The domain of the recipient. |
| rcpt_additional_data | JSON Object | Additional data of the recipient that was provided by you in Transmission API or Recipient List API. |
| from | String | Indicates the sender address. |
| subject | String | The subject of the transmission. |
| message_id | String | The message ID of the email that got bounced. |
| transmission_name | String | The name you provided for the transmission in Transmission API. |
| injected_time | Long | The time the transmission was created. |
| transmission_id | Long | The ID of the transmission. |
| zuid | Long | The ID of the user that sent the transmission API request. |
Bounce Reasons
| Bounce Extended Code | Bounce Reason | Description |
| 4.1.1 | Temporary mailbox address failure | The recipient's email address could not be found temporarily. |
| 4.1.2 | Temporary domain address failure | Temporary issue with the domain name of the recipient. |
| 4.2.0 | Mailbox temporarily unavailable | The mailbox is temporarily unavailable, possibly due to a server issue. |
| 4.2.2 | Mailbox full | The recipient's mailbox is full and cannot accept new messages. |
| 4.2.3 | Message length exceeds | Indicates that the message contains attachments or text that exceeds the system's message length limit. |
| 4.2.4 | Mailing list expansion problem | The mailbox is a mailing list address and the mailing list was unable to be expanded. |
| 4.3.1 | Mailsystem full | The mail server is temporarily out of resources. |
| 4.3.2 | System not accepting network messages | This could be due to various reasons, such as an unplanned shutdown, system maintenance, or excessive load. |
| 4.3.3 | System not accepting messages | This could be because the message contains features not supported by the receiving system. |
| 4.3.4 | Message too big for system | Message size limit has been exceeded. |
| 4.3.5 | System incorrectly configured | The server configuration might have errors or incorrect values. |
| 4.4.1 | No answer from host | Temporary failure due to network issues between servers. |
| 4.4.2 | Bad connection | Mail server timed out while trying to connect to the recipient’s server. |
| 4.4.3 | Directory server failure | This error indicates that the email was temporarily delayed or rejected due to issues with routing the message through the recipient's mail server or across intermediate servers. |
| 4.4.4 | Unable to route | Indicates network issues, including broken routing. |
| 4.4.5 | Mailsystem congestion | The message was undelivered due to the recipient's email network being congested or overloaded. |
| 4.4.6 | Routing loop detected | A routing loop was detected due to a network issue, and the email message was forwarded repeatedly. |
| 4.4.7 | Delivery time expired | Indicates that an email could not be delivered to the recipient's mailbox within a specified time. It suggests a delay rather than a permanent failure. |
| 4.4.8 | MX policy error | This error usually indicates an issue with the destination domain's MTA-STS policy not containing the MX host. |
| 4.5.1 | Invalid command | The message was undelivered due to an invalid command by the sender's email provider. |
| 4.5.3 | Too many recipients | The message has more than 200 SMTP envelope recipients from the same domain. |
| 4.5.5 | Wrong protocol version | This error indicates that there was a protocol mismatch or error during the communication between the sending and receiving mail servers. |
| 4.6.0 | Content not accepted | This error occurs when the recipient’s mail server encounters an issue with the message content, such as encoding, encryption, etc. |
| 4.6.1 | Media not supported | This error indicates that the email was temporarily rejected because the receiving server could not process the media type or content format of the message. |
| 4.7.1 | Delivery not authorized | The sender may not be authorized to send to the destination. |
| 4.7.2 | Mailing list expansion problem | The recipient's email provider has blocked your email address from posting messages to this mailing list. |
| 4.7.26 | Authentication problem | This error indicates that the message was not delivered due to SPF or DKIM failures. |
| 4.7.7 | Message integrity failure | This error indicates that the message was not delivered because it was corrupted or altered. |
| 4.7.8 | Authentication problem | This error indicates that the message was not delivered due to an incorrect username or password provided by the sender's email system. |
| 4.7.10 | Encryption needed | The message was rejected because it was not encrypted, but encryption was expected. |
| 4.7.12 | Password transition needed | This error indicates that the message requires password for authentication. |
| 4.7.15 | Priority level too low | This error indicates that the message has not yet been delivered due to a priority level lesser than which is acceptable by the email systems. |
| 5.1.1 | Bad destination mailbox address | The recipient's email address doesn't exist. |
| 5.1.2 | Bad destination system address | The domain part of the recipient's email is invalid or cannot be found. |
| 5.1.3 | Bad mailbox syntax | The email address format is incorrect. |
| 5.1.4 | Destination mailbox address ambiguous | The message could not be delivered because the recipient's email address is associated with more than one inbox. |
| 5.1.5 | Destination address invalid | It often occurs due to the recipient address being misconfigured, corrupted, or unavailable for routing. |
| 5.1.6 | Destination mailbox address has moved | The email address has changed, and no forwarding address is available. |
| 5.1.8 | Spam mail rejected | The account has been blocked for sending too much spam. |
| 5.1.10 | No MX for recipient | The recipient's <SMTP Address> wasn't found by SMTP address lookup. |
| 5.2.1 | Mailbox disabled | The recipient’s mailbox is disabled, possibly due to inactivity or deactivation. |
| 5.2.2 | Message quota exceeded | The recipient’s mailbox is full and cannot accept new messages. |
| 5.4.1 | Message rejected | This error is caused by mail server or DNS misconfiguration. |
| 5.4.6 | Routing loop detected | A configuration error has caused an email loop. |
| 5.4.8 | MX policy error | This error usually indicates an issue with the destination domain's MTA-STS policy not containing the MX host. |
| 5.5.2 | Syntax error | The sender's email address syntax is invalid. |
| 5.5.3 | Too many recipients | There were too many recipient addresses in the "To", "CC", or "BCC" field. |
| 5.7.1 5.7.12 | Authentication failure | The email was rejected due to permission issues (e.g., sender is not authorized). |
| 5.7.13 | User account disabled | The message could not be delivered because the email account for sender's email is disabled. |
Sample payload for a bounce event
Copied{
"webhook_name": "Bounce webhook",
"webhook_id": "1314909000000063002",
"action": "bounce",
"actionType": "hardBounce",
"data": [
{
"bounce_extended_code": "5.1.2",
"bounce_type": "hardbounce",
"bounce_code": "554",
"bounce_reason": "bad-domain",
"action_time": 1725543459000,
"sending_ip": "135.84.83.99",
"contact_id": 1314909023300000144084,
"contact_email": "john.doe@zylker.com",
"rcpt_domain": "zylker.com",
"rcpt_additional_data": {
"country": "JP",
"ph": "1239333320"
},
"from": "\"Aaron Fletcher\" <aron@zylker.com>",
"subject": "Summer is here",
"message_id": "<zcb.3z48a08b0c5ad7835216d2d705c1539aa2a44504764ccc7f4bbeceff75d3b82de0.1123f7ec4d0f91a09.1725514638987@bounce.zylker.com>",
"transmission_name": "My first Email API Campaign",
"injected_time": 1725543431000,
"transmission_id": 1314909000000112344068,
"zuid": 8575431221455
}
]
}
