A regular landing page on react does not work on hosting, how to fix it?

Question

React

I uploaded a page on react to the hosting.
Everything is simple - landing, I used several libraries, at first everything was fine.
After the npm run build command, all the contents loaded - everything worked.
After connecting redux-form, after uploading to the hosting, there is just an empty page
. There are no errors in the console.
Tried empty app after npx create-react-app also empty page
What's wrong with react?
The previous questions suggest:

1) write npm run build
2) Throw all files from the build folder to the root (hosting)

Why doesn't this method work anymore?