When hostname is not set in the system, such error is occured: check_ntlm_password: Checking password for unmapped user [NODOMAIN]\[USER]@[] with the new password interface check_ntlm_password: mapped user is: []\[USER]@[] check_ntlm_password: Authentication for user [USER] -> [USER] FAILED with error NT_STATUS_NO_SUCH_USER Please, add appropriate hostname checks to make debug output more understandable.