sendmail question

[Mail Monitor]

Hi,

I'm running sendmail on FreeBSD 4.7 and have a
problem with sendmail.

Even though the sendmail is running, the
mails are not coming into the server.

I tried sending a mail from command line using
/usr/sbin/sendmail -v abc at xxx.yyy. The output
of this command hangs just before DATA i.e
EHLO, MAIL from are supported. But i donot get
"Recipient ok" it takes 10 min to complete the
mail delivery and hangs after "RCPT To" for 10 min.

Any clue why it happens?

Thanks