GKAccessPoint fails on macOS

this GKAccessPoint code fails on macOS. The AccessPoint button appears, but disappears when clicked -- no modal window. works fine on iOS but not macOS. what am i doing wrong?

import SwiftUI
import GameKit

struct AccessPoint: View {
    var body: some View {
        ZStack {
            Color.clear
            Text("GKAccessPoint")
        }
        .onAppear() {
            GKLocalPlayer.local.authenticateHandler = { viewController, error in
                GKAccessPoint.shared.isActive = true
            }
        }
    }
}