If you want to use a specified SMTP, please fillin following fields. (You may consult your ISP about this SMTP information.)
Host - Your SMTP Host
Port - By default, you should use 25.
Connection Security - If your SMTP server requires SSL/TLS connection, you can choose it here.
Server requires authentication - If your SMTP server requires authentication, please check this box. You need to provide the Username and Password.
Username - Username to access SMTP server.
Password - Password to access SMTP server.
If you prefer to use RoboMail built-in SMTP server, check the box at bottom. Please consult your ISP and ensure they allow you to run your own SMTP server without blocking port 25.