SMTP Outbox won't send

[dbaechtel]

I have set up Outlook 2003 to get my email from
Compuserve. It uses IMAP4 for input and SMTP for outgoing.
Reading the email is working OK. But i replied to an
incoming email, the reply went into the Outlook Outbox,
but nothing I do will cause it to be sent. Send/Receive
All does not empty the Outbox and neither does Send All.
If reading the mail works, how do I get the Outbox to
send the reply?