LDAP with Active Directory connection
Just a note for the LDAP doc on the redmine site,
at least in my case, te surname attribute at the section of automatic account creation at LDAP, is not called "sN" as your ldap doc said, is only "sn".
After some failed logons, I navigate the active directory tree at my DC with ldp.exe tool and find at an account that attribute name different, so until I corrected it was impossible to login, in spite of sucessfull LDAP test connection.
Please update it to help other people that could have same problem.