Unable to receive messages in the Raspberry Pi connection example

I followed the steps mentioned in "Getting started with AWS IoT Core" documents to test my Raspberry Pi 4B device connectivity. I have created certificates, policy that allows connect, subscribe and publish actions for any (*) resource and created a thing entry for my device.

I have tried both Python and Node samples. In both the cases the client is able to publish messages, but no messages are getting consumed i.e. received. From Amazon Console I can test the same by subscribing to the same topic from console. It is successfully receiving messages. I am facing problem in sample code.

There are no errors. Only publish messages get printed and the program waits forever to receive the messages.

Any pointers?