4.2.0 Email Bounce Error
Reason
Unknown Issue With Mailbox: Delayed Message
The email message has not yet been delivered because of a problem of some sort with the recipient’s email inbox.
How to fix?
Check the recipient’s email address for misspellings or missing letters. If an error is found, correct it in contacts list or address book for next time.
4.2.0 – Official definition from ITEF
For the code that starts from 4.X.X
A persistent transient failure is one in which the message as sent is valid, but persistence of some temporary condition has caused abandonment or delay of attempts to send the message. If this code accompanies a delivery failure report, sending in the future may be successful.
For the code that starts from X.2.0
The mailbox exists, but something about the destination mailbox has caused the sending of this DSN.
5.2.0 Email Bounce Error
Reason
Unknown Issue With Mailbox: Message Not Delivered
The message could not be delivered due to a problem of some sort with the recipient’s email inbox.
How to fix?
Check the recipient’s email address for misspellings or missing letters. If an error is found, correct it in contacts list or address book for next time.
5.2.0 – Official definition from ITEF
For the code that starts from 5.X.X
A permanent failure is one which is not likely to be resolved by resending the message in the current form. Some change to the message or the destination must be made for successful delivery.
For the code that starts from X.2.0
The mailbox exists, but something about the destination mailbox has caused the sending of this DSN.
