This message contains a request to send a notification about your reception of the message. It contains a processing instruction that is marked as "required", but which is unknown to KMail. You can either ignore the request or let KMail send a "failed" response.
Dit berjocht befettet in fersyk foar in ûntfangst - en lêzen befêstiging. It befettet in ynstruksje dy markearre is as "fereaske", mar net bekend is by KMail. Jo kinne dit fersyk negearje of KMail in antwurd yn de foarm fan "mislearre" stjoere te litten.