4.4.3 Email Bounce Error
Reason
Network Issue With The Receiving System: Delayed Message
The email message has not yet been delivered because a network problem prevented the recipient’s email provider from delivering the message.
How to fix?
The sender’s email system will retry this message a few more times and provide further updates. If the sender is not notified within a few days that the message was delivered, try sending it again. Or contact the recipient another way, such as phone or text message.
4.4.3- 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.4.3
The network system was unable to forward the message, because a directory server was unavailable. This is useful only as a persistent transient error. The inability to connect to an Internet DNS server is one example of the directory server failure error.
5.4.3 Email Bounce Error
Reason
Network Issue With The Receiving System: Message Not Delivered
The message could not be delivered because a network problem prevented the recipient’s email provider from delivering the message.
How to fix?
The sender’s email system will retry this message a few more times and provide further updates. Iif the sender is not notified within a few days that the message was delivered, try sending it again. Or contact the recipient another way, such as phone or text message.
5.4.3- 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.4.3
The network system was unable to forward the message, because a directory server was unavailable. This is useful only as a persistent transient error. The inability to connect to an Internet DNS server is one example of the directory server failure error.
