Today I've come to set up Windows Live Mail 2012 so my dad can access his emails when he needs to, he has a supanet account. I've went through the steps: provided account details, server ports and connections, ticked that it needs authentication when sending and everything like that. It's loaded all his emails perfectly fine but when I'm testing the send function it keeps giving me:

The message could not be sent. The setting for your outgoing email [SMTP] server might need to be configured. To find the server settings for *** Email address is removed for privacy ***', please contact your email service provider.

Subject 'test19'
Server Error: 550
Server Response: 550 You need to authenticate when sending from ***.***.**.*** (IP address)
Server: 'smtp.supanet.com'
Windows Live Mail Error ID: 0x800CCC79
Protocol: SMTP
Port: 25
Secure(SSL): No

Can anyone help me fix this please