#25 Cannot use smtpd from a remote machine

[terence8888]

I have hotwayd/hotsmtpd installed on my FC4 server.
Everything works fine. Thunderbird will quite happily
send mail thru hotsmtpd.

However, but error occurs when I try to send mail thru
hotsmtpd (on the server) from a remote XP machine. I
can telnet hotsmtpd from the same machine though.
Tried Outlook XP and Mozilla mail and same thing happened.