This message was relayed to the monitoring system from syslog: sendmail[15922]: k0N7oYh15922: to=dfv, delay=00:00:00, mailer=local, pri=0, dsn=5.1.1, stat=User unknown
Jan 23 08:50:34 hostname sendmail[15922]: k0N7oYh15922: k0N7oYi15922: DSN: User unknown
Next the system didnt recognise any...