maillog extract

Hi all, below are some text extracted from maillog. I have a cronjob running at 1720 daily and it will send mails to me. it was working fine on the 27 Sept.

Sep 27 17:20:01 venus sendmail[32711]: k8R9K0OR032710: from=user1, size=580, class=0, nrcpts=1, msgid=<200609270920.k8R9K0OR032710@venus.domain.com>, relay=user1@localhost
Sep 27 17:20:01 venus sendmail[32711]: k8R9K0OR032710: to=user1, ctladdr=user1 (502/502), delay=00:00:01, xdelay=00:00:00, mailer=relay, pri=30580, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Sep 27 17:20:01 venus sendmail[32716]: k8R9K1Vq032713: from=user1, size=175, class=0, nrcpts=6, msgid=<200609270920.k8R9K1Vq032713@venus.domain.com>, relay=user1@localhost
Sep 27 17:20:01 venus sendmail[32716]: k8R9K1Vq032713: to=abccba@hotmail.com, ctladdr=user1 (502/502), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=180175, relay=mail.domain.com. [111.11.111.111], dsn=2.0.0, stat=Sent (k8R9K2vh015544 Message accepted for delivery)

However, on the 30 Sept, i have stopped receiving mails.

Sep 30 17:20:02 venus sendmail[7453]: k8U9K0AH007413: from=user1, size=580, class=0, nrcpts=1, msgid=<200609300920.k8U9K0AH007413@venus.domain.com>, relay=user1@localhost
Sep 30 17:20:02 venus sendmail[7453]: k8U9K0AH007413: to=user1, ctladdr=user1 (502/502), delay=00:00:02, xdelay=00:00:00, mailer=relay, pri=30580, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]

I don't recall making any changes to my scripts. From the maillog on 30 sept, it seems that the relay field is set to the host itself. It is not supposed to be the case.
(1)Does anyone know how are the various fieldnames set?
(2)I also realise that the dsn values for success sending is 2.0.0 and failure sending is 4.0.0. Can i infer any clue here?
(3)is there anyway i can retrieve the message based on the msgid?

Try looking at your sendmail configuration - on Sept 27, the mail is being sent to a relay. On the 30th, it doesn't show that at all.

/usr/lib/sendmail -d0.1 -bt < /dev/null may give you a clue. Also check if any of your config files were changed between the 27th and 30th (config files may be in /etc/mail/).