The transport failed to connect to the server
This error can just pop up without any code changes at all! It has to do with directory permissions. In essence, the web account that is logged in attempting to send the mail message does not have access to the "pickup" directory where the mail message needs to go to be sent!
Go to your INETPUB directory on your hard drive. Navigate down to MAILROOT, then PICKUP. Set the PICKUP directory to have full access from IUSR_MACHINENAME where that username matches whatever you use for anonymous web access to your website. Voila!
ASP Mail Code and Troubleshooting