Hi Can anyone help me with this error message when trying to send...only send ...it is receiving fine. Thanks

The message could not be sent because the server rejected the sender's email address. The sender's email address was *** Email address is removed for privacy ***'.  Subject 'TEST' Server Error: 530 Server Response: 530 Authentication required Server: 'smtp.ihug.co.nz' Windows Live Mail Error ID: 0x800CCC78 Protocol: SMTP Port: 25 Secure(SSL): No