qmail-pop3d - problem logging in

[Boz Crowther]

I'm getting the following error message when trying to log in to my qmail server via pop3.  I've confirmed that checkpassword is working properly, using the instructions on the installation web page.  Any suggestions?   There was a problem logging onto your mail server. Your Password was rejected. Account: '192.168.20.16', Server: '192.168.20.16', Protocol: POP3, Server Response: '-ERR authorization failed', Port: 110, Secure(SSL): No, Server Error: 0x800CCC90, Error Number: 0x800CCC92