Entrypoint refers to the identity of a site in a multisite deployment. All security groups and Group Policy Objects are displayed ...

Entrypoint refers to the identity of a site in a multisite deployment. All security groups and Group Policy Objects are displayed for all sites except downlevel security groups and downlevel Group Policy objects which are displayed only for the specified site they belong to (i.e., these clients connect only to this site).

If there is a multisite deployment then down-level client security group and Group Policy object information is always retrieved only for a specific site. If the entrypoint is not specified then the site to which the computer on which the cmdlet is executed is used (user may or may not be specifying a ComputerName). It is not possible to retrieve all the down-level security groups and Group Policy objects across all sites

If both entrypoint and computername are specified and the ComputerName doesnt belong to the site represented by the entrypoint then the entrypoint takes precedence and the authentication type is configured for it

If there is no multisite deployment but user specifies the entrypoint param then the cmdlet returns an error message