What protocol cannot be used with the active authentication type?

Local user authentication is an active authentication type where users provide credentials directly to the FortiGate.

RADIUS is a standard protocol used for active authentication, where the FortiGate forwards user credentials to a RADIUS server for verification.

LDAP is commonly used for active authentication, allowing the FortiGate to query an LDAP server (like Active Directory) to validate user credentials.

RSSO (Remote Single Sign-On) is a passive authentication mechanism where user identity is learned from an external source (like FortiAuthenticator or Active Directory) without the user actively providing credentials to the FortiGate itself. In contrast, active authentication requires direct user input of credentials (e.g., username/password) to the FortiGate or an external server.