Below is a warning customers get can anyone help.
The page is users_registration
Warning: mail() [function.mail]: SMTP server response: 503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server. in C:\Inetpub\vhosts\wheelyunique.com\httpdocs\WA_Universal_Email\mail_PHP.php on line 254
Warning: Cannot modify header information - headers already sent by (output started at C:\Inetpub\vhosts\wheelyunique.com\httpdocs\WA_Universal_Email\mail_PHP.php:254) in C:\Inetpub\vhosts\wheelyunique.com\httpdocs\users_Profile.php on line 142