MQTT subscribe not working in Android

Question

I am trying to get a message from the MQTT Broker using the Android service, but it does not work.

The library used is the Paho MQTT library, and the source code is as follows.

final MqttConnectOptions hIoTConnectionOptions = new MqttConnectOptions();
hIoTConnectionOptions.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1);
hIoTConnectionOptions.setAutomaticReconnect(true);
hIoTConnectionOptions.setCleanSession(false);`

try {
    hIoTAndroid = new MqttClient(ip_addr, clientID, new MemoryPersistence());
    IMqttToken conToken = hIoTAndroid.connectWithResult(hIoTConnectionOptions);
    hIoTAndroid.setCallback(MqttMessagingService.this);
    conToken.setActionCallback(new IMqttActionListener() {
        @Override
        public void onSuccess(IMqttToken asyncActionToken) {
            Log.d(TAG, "onSuccess");
            hIoTAndroid.setCallback(MqttMessagingService.this);
            try {
                IMqttToken subToken = hIoTAndroid.subscribeWithResponse(subtopic, 1);
                subToken.setActionCallback(new IMqttActionListener() {
                    @Override
                    public void onSuccess(IMqttToken asyncActionToken) {
                        Log.i(TAG, "Successfully subscribe to: " + subtopic);
                    }

                    @Override
                    public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                        Log.d(TAG, "Couldn't subscribe to: " + subtopic);
                    }
                });
            } catch (MqttException | NullPointerException ex) {
                ex.printStackTrace();
            }
        }
        @Override
        public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
            Log.d(TAG, "Failed Connection");
        }
    });
} catch (MqttException ex) {
    Log.d(getClass().getCanonicalName(), "Connection attempt failed with reason code = " + ex.getReasonCode() + ":" + ex.getCause());
}


@Override
public void connectComplete(boolean reconnect, String serverURI) {
    Log.d(TAG, "Connection is established....");
}

@Override
public void connectionLost(Throwable cause) {
    Log.d(TAG, "The Connection was lost,,");
}

@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
    Log.i(TAG, new String(message.getPayload()));

}

@Override
public void deliveryComplete(IMqttDeliveryToken token) {
    Log.d(TAG, "Sent Message !");
}

The publish and deliveryComplete functions work fine, but the subscribe function and messagArrived do not work. Why?