4.6.3 Email Bounce Error
Reason
Message Content Could Not Be Processed For Delivery: Delayed Message
The email message has not yet been delivered because it included content or attachments that needed to be converted, which the email system was unable to accomplish.
How to fix?
If the message had attachments, try sending it again without them and then try sending each attachment in a separate email. If this error occurs when there are no attachments, check the text of the message for unusual content or characters. If this error persists, contact the email provider for help.
4.6.3- 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.6.3
The message content must be converted in order to be forwarded but such conversion is not possible or is not practical by a host in the forwarding path. This condition may result when an ESMTP gateway supports 8bit transport but is not able to downgrade the message to 7 bit as required for the next hop.
5.6.3 Email Bounce Error
Reason
Message Content Could Not Be Processed For Delivery: Message Not Delivered
The message could not be delivered because it included content or attachments that needed to be converted, which the email system was unable to accomplish.
How to fix?
If the message had attachments, try sending it again without them and then try sending each attachment in a separate email. If this error occurs when there are no attachments, check the text of the message for unusual content or characters. If this error persists, contact the email provider for help.
5.6.3- 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.6.3
The message content must be converted in order to be forwarded but such conversion is not possible or is not practical by a host in the forwarding path. This condition may result when an ESMTP gateway supports 8bit transport but is not able to downgrade the message to 7 bit as required for the next hop.
