If you are entering in the correct login, then you must be using the wrong password for this particular POP3 account. It is very important to remember that both the login and the password are case sensitive! Try several times, making sure that you are entering in your login and password correctly. Remember that you determined the login and password for this account through your Control Panel!
If you cannot get in, do not panic! This is a problem that is easily corrected. Take the following steps one by one to correct this problem:
1. Log into your Control Panel using your account username and your account password.
2. Select "Mail" then select "Change Password" for the account you are having problems with.
3. Now type a new password for this POP3 account.
4. The password for this POP3 account has now been changed, and you can check for e-mail on this POP3 account using the login and the new password.