[Dovecot] Error: no authentication failed

[gaoqiang.qian]

Hi,
I have installed the dovecot on my redhat linux host. But when I log in
with dovecot/test I got Error: no authentication failed after I got ok
dovecot ready when I connect to local host. dovecot/test  was set in the
password.dovecot file. But I do not know how can I use this username and
password in the configuration file.
Could anyone give me a hand to let me know how to configurate the
username and password for login.
Thanks