unable to Sub scribing with Mqtt data in AWS IoT core with greengrass deployment

Hi. To publish or to subscribe to IoT Core from a Greengrass component, the recommended way is to use the messaging IPC service: https://docs.aws.amazon.com/greengrass/v2/developerguide/ipc-iot-core-mqtt.html

It is possible to use an MQTT client directly from within a component to connect to IoT Core. The client would have to meet one of the IoT Core client authentication methods. Most commonly, an X.509 certificate. IPC is preferred though and takes advantage of the Greengrass core device's existing identity.