[Dovecot] authentication failure with known good credentials???

Hi,

I have a problem on my server. To illustrate, I created a new user,
unclewiggly, and set up a password. I then used sent an email from my
usual account. Logging in with my browser I am able to see the inbox,
the mail and contents correctly. I then set up a new instance of
Eudora 7.1 on my windows 7 box with the appropriate login id and check
the account using the correct password. The fetch fails with the
client reporting an authentication failure.

Ideas? Places to look? Logfiles I can search? Maillog doesn't seem
very informative, should I send a snippet?

Thanks,

Dave

-- "It is no measure of health to be well adjusted to a profoundly sick society." Krishnamurti