Logon on to Computername

Does anyone know what’s the servername (computername) to put on the AD user account properties : Log On To , so that he can authenticate with spark using ldap ? I did put in the servername of the computer that openfire is installed. But the user still can’t authenticate with the server. When I remove the logon on to restriction, the user can authenticate fine… I can’t figure out the correct server’s name…Any advice is appreciated…Thanks,