Get information about AD authentication

I installed LdapContrib as well as all dependencies.
I set (in Extensions ---> LDAP) host name, port BindDN and BindPassword. In 'Security and Authentication' ---> Password, I change PasswordManager to Foswiki::Users::LdapPasswdUser.

In 'LDAP' extension setting, I checked {Ldap}{Debug}.
However, when I try to Log in, I need to wait some time and then I see an authentication error (without any detailed information).
Is it possible to check what goes wrong? How I will be able to check what was done/tried at each step? Where logs are saved?

-- RomanAndrzej - 08 Sep 2014