In the process of sending an e-mail, Bounce is the status when the e-mail server of a business or Internet service provider does not accept the e-mail sent to a specific e-mail address. Bounce status is divided into two as hard bounce and soft bounce.
Soft bounce is a temporary state depending on the recipient’s server at the time of sending. Soft bounce status may change into being transmitted over time.
Hard bounce, on the other hand, is a permanent condition and indicates that your recipient’s e-mail address is invalid. For this reason, you should not resend e-mails to your hard bounce recipients. In this case, removing the hard bounce members from your lists will help you use your transmission limit more efficiently and to prevent invalid members from occupying space in the member quota.
In the details of your e-mail transmission reports in euromsg express, the “Invalid” status information means it hard bounced, and “Not Reached” status information means it soft bounced.
What is Hard Bounce?
Hard bounce is a permanent status of your recipient member, usually indicating that the e-mail address is invalid and the server has permanently rejected the email. When you send an e-mail to a member who experienced hard bounce, it will cause your Internet service provider to be blacklisted, so your next e-mail to a member who experienced hard bounce will be blocked by the system.
What is Soft Bounce?
Soft bounce is an indication that the problem with your recipient member’s e-mail address is partially temporary. It indicates that the e-mail address is valid but the server rejects the incoming e-mail.
Since the status of the e-mail that you have sent to your recipient member who experienced soft bounce can change and get delivered, the following 2 e-mails you have sent will also be transmitted by the system to the member who experienced soft bounce. While this sending process, if the status of the recipient member is determined as soft bounce, the system marks this recipient member as hard bounce and your subsequent e-mails do not get sent to that member. When you send an e-mail to a member who experienced hard bounce, it will cause your Internet service provider to be blacklisted, so your next e-mail to a member who experienced hard bounce will be blocked by the system.
Hard Bounce and Soft Bounce Codes with Explanations
| Kod | Type | Explanation |
| 500 | Hard | Invalid Address |
| 510 | Hard | Unknown User (Invalid Address) |
| 511 | Hard | Unknown User (Invalid Address) |
| 512 | Hard | Unknown Domain (Invalid Address) |
| 515 | Hard | Wrong e-mail address (Invalid Address) |
| 516 | Hard | Mailbox Has Been Moved |
| 520 | Hard | Invalid Address |
| 524 | Hard | E-mail list expanding problem |
| 532 | Hard | System does not accept network messages |
| 540 | Hard | Wrong e-mail address (Invalid Address) |
| 544 | Hard | No MX record found for the relevant domain. |
| 546 | Hard | Redirect loop detected |
| 550 | Hard | Non-existing e-mail address (Invalid Address) |
| 551 | Hard | Non-existing e-mail address (Invalid Address) |
| 553 | Hard | Requested action is not taken / Invalid mailbox |
| 555 | Hard | Syntax (Incorrect character) error / Invalid address |
| 513 | Hard/Soft | Incorrect e-mail address (Invalid address) / Sender needs to verify the address. |
| 521 | Soft/Hard | Mailbox is disabled, not accepting e-mail. / Mailbox is inactive |
| 530 | Soft/Soft/ Hard | Authentication is required/ Blacklisted / Invalid member address |
| 554 | Soft/Hard | Operation Failed, Firewall blocking / Invalid address by Yahoo |
| 421 | Soft | Service unavailable – Connection time out |
| 450 | Soft | Sender Domain not found |
| 451 | Soft | Sender Domain not found – Configuration error |
| 452 | Soft | Insufficient system space – Insufficient system memory |
| 517 | Soft | Invalid sender address (Spf authentication or MX record) |
| 522 | Soft | Mailbox is full (Quota) |
| 523 | Soft | Message length exceeds administrative limit (Unable to accept message) |
| 541 | Soft | Access denied – Cannot get through the anti spam program |
| 543 | Soft | Spam suspected, blocked |
| 552 | Soft | Mailbox limit exceeded |
| 560 | Soft | Service denied |
| 570 | Soft | Other or unspecified security status |
| 571 | Soft | Transmission is not authorized, message denied |
| 572 | Soft | Denied transmission to inactive e-mail address |
| 577 | Soft | Message integrity error – Message cannot be accepted |
