You have sendmail running, or so it appears.
Mar 24 11:20:02 mail sendmail[2474]: k2OHK2xX002474: from=zimbra, size=393, class=0, nrcpts=1, msgid=<200603241720.k2OHK2xX002474@mail.myagilon.c om>, relay=zimbra@localhost
Mar 24 11:20:02 mail sendmail[2474]: k2OHK2xX002474: to=zimbra, ctladdr=zimbra (501/501), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30393, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
You need to kill this and make sure it doesn't start on reboots.
chkconfig sendmail off |