Solving “Proxy error: Could not proxy request xxx from yyy” from local ReactJS app to NodeJS app

How to fix “Proxy error: Could not proxy request xxx from yyy” in local NodeJS app

So, while I am calling from a ReactJS app, listening on port 3000, locally to also locally running NodeJS app, listening on port 8000, I was using the proxy parameter in package.json in ReactJS. But I was getting the following error.