Hi,
Have you tried adding your domain to the default domains of the SSO? Just login to the webclient with admin@System-Domain and you should be able to edit these settings under Administration.
Also check under administration | Sign-on and Discovery | configuration - have you get an Identity source set ?
Should add one if not Server URL: ldap://<domain controller type: active directory domain: your AD domain alias your AD netbios name
Many tx
Many tx