getting error while trying to send mail

Message: mail(): SMTP server response: 550 Access denied - Invalid HELO name (See RFC2821 4.1.1.1)
here is my php.ini

[mail function]

; For Win32 only.

;http://php.net/smtp

;SMTP=localhost

SMTP=mail.substantiator.com

; http://php.net/smtp-port

smtp_port=465



; For Win32 only.

;http://php.net/sendmail-from

sendmail_from [email protected]





; For Unix only.  You may supply arguments as well (default: "sendmail -t -i").

; http://php.net/sendmail-path
;sendmail_path =

here is my code:

mail($to,$subject,$message,$headers);

Where does the required username and password go? 

proof that an old dog can learn new tricks