Does build/index.html generated after npm run build serve as a standalone webpage or does it only work with serve -s build.
index.html file returns blank page and on inspecting the page it shows: "main.17cbfec0.js:1 Failed to load resource: net::ERR_FILE_NOT_FOUND"
You should serve the entire build directory, not just specific files as the index.html file relies on various JavaScript bundles generated by CRA, which are all located in that build folder.
build
index.html