need help - the client cannot download mail

[Sobari Tanuwijaya]

Hello,
I just installed the qmail here.
everything is fine, except the user(s) in the system cannot 
download their mail from the server ( which use qmail ).
Everytime the user try to download the mail it prompt
that the password is not correct, eventhough the user already give 
the right password.
anybody can help me how to correct this problem ?
the user use pegasus mail as his mail client.
Thanks in advance


Have a nice day !

Regards,

Sobari Tanuwijaya