The mail send to the manager is received but is not processed by the manager: why?

One of the reasons can be that the mail has been forwarded and the mail client is making an attachment from the mail you are forwarding. In that case the Kyocount xml attachment is an attachment in an attachment and the manager cannot process it anymore.
It can happen that when the mail is marked as read on the mail server it cannot be read again as KYOcount is checking the mail server for new mail only. In this case mark the mail as unread on the mail server.
An other less likely reason can be that the xml file has been edited manually and therefore the ‘signature key’ inserted by Kyocount into the xml file is no longer valid.