Can't setup new email account

I am trying to set up a new email address. I have duplicated exactly my
other 2 addresses properties but it won't work. When I click on send/receive
everything is fine with the first 2 email address but with the new one it
asks for username and password. It won't accept what I enter, so when I
cancel, the error I get is copied below:

Account: ' (2)', Server: '', Protocol:
POP3, Server Response: '-ERR Invalid login or password', Port: 110,
Secure(SSL): No, Server Error: 0x800CCC90, Error Number: 0x800CCC92

I am using AVG Anti-Virus Free .Hope someone can help. Thank you.