Got error 403 (Forbidden) when importRoute using Here Android SDK

Question

I'm trying to import a list of Location to calculate the route (using Here Android SDK). However I always got error: (403) Forbidden.

Here SDK's guide: https://developer.here.com/documentation/android-sdk-explore/4.10.5.0/dev_guide/topics/routing.html#import-routes-from-other-services

I've checked key, key_secret and appID for my project, every things is fine. Here is my code:

val routingEngine = RoutingEngine()
routingEngine.importRoute(
     generateGeoLists(),
     CarOptions()
) { routingError, routes ->
    if (routingError == null) {
        routes?.getOrNull(0)?.let {
            showRouteOnMap(it)
        }
    } else {
        DebugLog.d("Error import", "import failed: $routingError")
    }
}

Please help me to solve this.

Note: Other methods like 'calculateRoute',... work fine except 'importRoute'. I'm using Here SDK Explore edition.