Message Not Delivered: Bad messaging command in transmission
The message could not be delivered because the sender's email provider used a messaging command that was unsupported.
Retry the email message see if it was a one-time problem or if the same error occurs.
Otherwise, contact the support team as the sender's mail system issued a command that is not supported by the recipient's email provider. This typically requires helpdesk support.
5.5.1: Official Definition
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.
A mail transaction protocol command was issued which was either out of sequence or unsupported. This is useful only as a permanent error.