sendmail is not functioning on FreeBSD 5.4

[pkrisada at ego.co.th]

Hi all,

Firstly, I'm sorry if this message is put in wrong mailing list.
Normally I use sendmail to send mails from my host to other hosts.
I can send any mails using mutt mail client to any addresses like...
hotmail, yahoo mail, and many more without any problems.
As now I have switched to FreeBSD 5.4-RELEASE and still use sendmail.
I have just subscribed to freebsd-stable at freebsd.org.
The problem is that I couldn't send any mails to freebsd-stable at freebsd.org,
while sending to other addresses is still nice on FreeBSD 5.4.
I'm a noobie. Anyone have clues please point me out.
Which configuration files shall I look at? Any ideas would be much
appreciated.
(This mail was delivered because I used web-based mail to send to same
address)

Thanks,
pongthep