Single Sign-On (SSO) is a holistic approach to authenticate users when signing on to applications in Azure Active Directory. If you enable SSO, a user only needs one login credential to access multiple applications, irrespective of the platform, domain, or technology used. Without SSO, a user needs a separate credential to access each application. The NAS supports SSO. Depending on which domain service the NAS joins, the device will synchronize the domain account information with the appropriate service.