4.5.5 Email Bounce Error
Reason
Email Systems Were Incompatible: Delayed Message
The email message has not yet been delivered because the sending email program and the recipient’s email program are using incompatible versions of software.
How to fix?
Try sending the message again in a while, since this problem might be temporary, or already in the process of being fixed. If this error persists, contact the email provider for help.
4.5.5- 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.5.5
A protocol version mis-match existed which could not be automatically resolved by the communicating parties.
5.5.5 Email Bounce Error
Reason
Email Systems Were Incompatible: Message Not Delivered
The message could not be delivered because the sender’s email program and the recipient’s email program are using incompatible versions of software
How to fix?
Try sending the message again in a while, since this problem might be temporary, or already in the process of being fixed. If this error persists, contact the email provider for help.
5.5.5- 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.5.5
A protocol version mis-match existed which could not be automatically resolved by the communicating parties.
