I am trying to send an email from my asp.net application, the function worked fine on my machine, but when I deployed it on the webserver, I got the error :The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required,
Any one can help? Thanks
Finally I managed to solve it, The SSL should be enable on the webserver as well, here is a link to enable ssl on the IIS7
http://weblogs.asp.net/scottgu/archive/2007/04/06/tip-trick-enabling-ssl-on-iis7-using-self-signed-certificates.aspx