How does the Endpoint Security Client communicate with the Container APP?

I've developed a Endpoint Security system extension, which will be installed in a container APP.

I use XPC to send message from container APP to the ES client, it works fine.

I have developed an Endpoint Security system extension that will be installed in a container app.

I utilize XPC to send messages from the container app to the ES client, and it functions properly. However, when I attempt to send messages from the ES client to the container app, it always displays an error: 'Couldn’t communicate with a helper application.'.

I have removed the sandbox capability of the container app and also employed the same app group for both the ES client and the container app. When an XPC client is connected, I use the following code in the ES client to establish two-way communication.

- (BOOL)listener:(NSXPCListener *)listener shouldAcceptNewConnection:(NSXPCConnection *)newConnection {
    newConnection.exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(NXFileGuardXPCProtocol)];
    
    NXFileGuardXPCService *xpcService = [NXFileGuardXPCService sharedInstance];
    newConnection.exportedObject = xpcService;
    
    // To APP container client (As remote interface)
    newConnection.remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(NXFileGuardXPCClientProtocol)];
    
    [newConnection activate];
    self.containerAPPConnection = newConnection;
    return YES;
}

But it always fails. How can I deal with this error?