If You Have Problems Sending Email...
You inserted code into your application to send email, but the email doesn’t appear to work.
Step 1: Configure your email server. See If You Have Problems Sending Email... for details
Step 2: Stop and restart the SMTP service in Microsoft IIS. We've found this works in many cases!
Step 3: Make sure your anti-virus or personal firewall software isn't blocking your email. Typically this involves granting access to port 25.
For example, McAfee VirusScan Enterprise 8.0 VirusScan Console, Access Protection, Properties, Port-Blocking tab, Rule:"Prevent mass mailing worms from sending mail". This blocks outbound access to any port 25 on the network. The Edit button shows a list of excluded processes to which new processes can be added.
Add the aspnet_wp.exe process to grant permission to send emails from port 25.