Using domain account to log in the server, and then configure the serv -u, Windows authentication, then according to the AD OU is configured the serv -u group, but on a visit to the FTP address, in addition to the current domain account verification through, other domain account to verify all is failure, always will be asked to enter account and password, check the log, and prompt invalid login name, consult everybody a great god, and is there a way to solve the problem?