When I try to send a message from my e-mail program, I get: 550

To prevent spammer from using our SMTP server, all users must be authenticated when using our SMTP server. To configure your SMTP server:

  1. Outlook Express. From your servers properties, check "My server requires authentication". Click "Settings" and make sure that you tick the box "Use same settings as my incoming server"
    Outlook Express SMTP settings

  2. Thunderbird/Seamonkey. From the e-mail settings, click Tools -> Accounts. In the SMTP settings, tick the checkbox "Use name and password".
    Thunderbird SMTP settings