As already pointed out, I see you are using 'Host = "127.0.0.1";' which is a localhost ip. This might not work on webserver. You need to have proper smtp server name to communicate.
Further, it can be because of other various reasons. Like: Is the port open? Firewall permissions in place?
I would suggest you to configure SMTP configuration in Web.Config:
<network host="somesmtpserver" port="25" userName="name" password="pass" defaultCredentials="true" />