Keep getting this, on brand new windows 7 system, (The message could not be sent. The authentication setting might not be correct for your outgoing e-mail [SMTP] server. For help solving this problem, go to Help, search for "Troubleshoot Windows Live Mail", and read the "I'm having problems sending e-mail" section. If you need help determining the proper server settings, please contact your e-mail service provider.

The rejected e-mail address was 'dsjordan@activ8.net.au'.

Subject 'Fw: Pure Water Systems'
Server Error: 451
Server Response: 451 http://www.spamhaus.org/query/bl?ip=61.68.229.242
Server: 'mail.activ8.net.au'
Windows Live Mail Error ID: 0x800CCC79
Protocol: SMTP
Port: 25
Secure(SSL): No)

Can you send email to other recipients okay? Spamhaus is a DNS Blacklist service. This error would indicate that that email address has been listed as a source for spam.

Still not sure about spamhaus, but got going by changing out going mail server to smtp.