MMS Notification - Executable Attachment not Stripped

[MMS-Admin]

The message you just sent to <address@hidden> contained
executable attachments that could not be removed.
the following files could not be deleted:
        details.pif (contained in your_details.zip)

The original message has not been delivered.  Please remove these
attachments or change the file extension before attempting to resend
your message.

Thank you!