Step one: Log on with your full email address, not just the part before the @

To configure a standalone mail client, the following information will be useful:
POP3 or IMAP server: mail.[your domain].com or wombat.sevarg.net (for now).
Username: Your full email address (user@domain.com), not just the username.
SMTP server: mail.[your domain].com or wombat.sevarg.net (for now).
You will have to use SMTP authorization with the same username/password to send mail out.