Leopard, localhost POP3, MailServe

[G. A. Edgar]

Using "MailServe for Leopard 3.0.4", I want to get POP3 working for
localhost -- primarily for when some software sends a message to me by
mail. This is working on an Intel Mac Pro; it was working on a G5; but
it is *not* working on my new iMac. As far as I can tell, everything
is set up the same (both in MailServe and in Mail). But trying it
(yes, with the right password) I get in Mail :

The POP server łlocalhost˛ rejected the password for user łedgar˛

and in /var/log/mail.log :

Sep 23 08:17:03 dizzy ipop3d[79394]: Connection reset by peer, while
reading line user=??? host=UNKNOWN
Sep 23 08:17:03 dizzy ipop3d[79394]: pop3 service init from 127.0.0.1
Sep 23 08:16:13 dizzy ipop3d[78722]: Logout user=edgar host=localhost
[::1]
Sep 23 08:16:10 dizzy ipop3d[78722]: pop3 service init from ::1

...the reset presumably when I click "CANCEL" in Mail.

Why is the iMac different?

One guess ???
The working cases (the Mac Pro and the G5) were first done with Postfix
Enabler in previous OS versions, then switched to MailServe when
Leopard came in. But the iMac is Leopard only, so started directly
with MailServe, never having used Postfix Enabler. Is there maybe
(???) something done by Postfix Enabler that I need to do myself to get
this to work in Leopard on the iMac?