Active Directory (AD) is an ID store that requires that a shadow user be created on Cisco ISE for the admin login to work. A shadow user is a user account that is defined in the ISE internal database, but has the password set to external. This means that the user authentication is performed against an external identity source, such as AD, while the user authorization is based on the ISE admin group membership. A shadow user is useful when the admin wants to assign different roles or permissions to specific AD users, rather than using AD groups. To create a shadow user, the admin must check the External checkbox in the ISE admin user configuration, and make sure that the username matches the AD username. The shadow user must also be assigned to an ISE admin group that has the Type set to External123. References := 1: ISE Admin User Shadow AD Account Issue 2: ISE Admin user authentication from AD 3: Which ID store requires that a shadow user be created on Cisco ISE for the admin login to work?