I am not receiving any data on connection to websocket. The issue started from 12 noon yesterday.
Resolved. Do not know how
It happens for me as well - once connection is established, at times no updates flow in. At that point i simply restart my app 
One good hack would be to subscribe to ‘NSE_INDEX|Nifty 50’. If the market is open, you will receive update for Nifty 50roughly every 500 ms. If you don’t, just restart your app. My experience is with Python 3 stack.