I have made 2 copies of my python code. they are in different folders and they handle different API and access tokens. Code 1 handles API1 and code 2 handles API 2. So no interference there. I checked the subscription. One API expires 18 days later and another one expires after 26 days. Exact same copy. Yet, Code 1 starts collecting LTP data immediately as market opens, exactly as I expect it to do. Meanwhile, code 2 handling API2 does not collect LTP data. I stopped the code and started after 9:15 to check. Not collecting LTP data at all.
Never mind i found the issue. One instrument I had in my excel sheet was tata motors. I made this excel sheet of exchange tokens and instrument tokens long time back. Tata motors probably split or something similar, so the instrument token exchange token was outdated and wrong.