For many channels, delivery history information is appended
    to the end of each message file after an unsuccessful delivery
    attempt has been made. With the HISTORY command, this information
    can be displayed.

    The messages to show histories for are specified by their message
    identification numbers shown by the most recent DIRECTORY
    command. That number appears in the leftmost column of the
    DIRECTORY command listing.

    Note that history information is not recorded by some channels.