X.1.3 Email Bounce Error [Bad destination mailbox address syntax]

4.1.3 Email Bounce Error

Reason

Email Address Malformed: Delayed Message

The recipient’s email address is not a valid email address and so email message has not yet been delivered.

How to fix?

Check the recipient’s email address for spaces or unusual characters. If an error is found, correct it in contacts list or address book for next time. If necessary, contact the recipient another way to confirm their email address.

4.1.3 – 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.1.3

The destination address was syntactically invalid. This can apply to any field in the address. This code is only useful for permanent failures.

5.1.3 Email Bounce Error

Reason

Email Address Malformed: Message Not Delivered

The message could not be delivered because the recipient’s email address is not a valid email address.

How to fix?

Check the recipient’s email address for spaces or unusual characters. If an error is found, correct it in contacts list or address book for next time. If necessary, contact the recipient another way to confirm their email address.

5.1.3 – 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.1.3

The destination address was syntactically invalid. This can apply to any field in the address. This code is only useful for permanent failures.