Important note to clients regarding sending mail through your domain (using email servers associated with your domain):  Security measures implemented by some large Internet service providers mean that we must require authentication for all your email sent out through our sendmail (SMTP) servers.  If you are using your domain to send email, you must change your mail program settings to require authentication when using the sendmail server.

Here is what to do:  In Outlook/Outlook Express, go to Tools > Accounts > Mail > double-click with left button on a mail account for your email address at the domain we host for you.  Go to the Servers tab and put a check in the box that says "My server requires authentication".  Other email programs will have a similar option to accomplish the same result.  That's it!  Thank you.