I'm having some difficulty connecting to and sending emails via smtp.

I have an account--we'll call ACCOUNTX--which is a subdomain account on mars.lunarpages.com (so the homepage is ACCOUNTX.lunarpages.com).  My username is USERNAME and my password is PASSWORD.  These are the USERNAME/PASSWORD I use to login into my control panel.

When I use the following settings, I get an SMTP authentication error:

to=*any address*
from=USERNAME@ACCOUNTX.lunarpages.com
user=USERNAME@ACCOUNTX.lunarpages.com
password=PASSWORD
smtp server=mars.lunarpages.com

Here the tail of the SMTP log (everything in '<' and '>' are my comments) :

DEBUG SMTP: useEhlo true, useAuth true

DEBUG: SMTPTransport trying to connect to host "mars.lunarpages.com", port 25

DEBUG SMTP RCVD: 220-mars.lunarpages.com ESMTP Exim 3.36 #1 Mon, 16 Sep 2002 00:06:13 -0700
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.

DEBUG: SMTPTransport connected to host "mars.lunarpages.com", port: 25

DEBUG SMTP SENT: EHLO <my machine hostname>
DEBUG SMTP RCVD: 250-mars.lunarpages.com Hello <my machine hostname/ip>
250-SIZE
250-PIPELINING
250-AUTH PLAIN LOGIN
250-STARTTLS
250 HELP

DEBUG SMTP Found extension "SIZE", arg ""
DEBUG SMTP Found extension "PIPELINING", arg ""
DEBUG SMTP Found extension "AUTH", arg "PLAIN LOGIN"
DEBUG SMTP Found extension "STARTTLS", arg ""
DEBUG SMTP Found extension "HELP", arg ""
DEBUG SMTP: Attempt to authenticate
DEBUG SMTP SENT: AUTH LOGIN
DEBUG SMTP RCVD: 334 VXNlc<...>

DEBUG SMTP SENT: c3RvbmVnMUBzdG9uZWdh<...>
DEBUG SMTP RCVD: 334 UGFzc3dvcmQ6

DEBUG SMTP SENT: NVRHM<...>
DEBUG SMTP RCVD: 535 Incorrect authentication data

Thanks in advance for any help-
daniel