Issue with generated react build from react scripts

I created a react project with scripted reactions. After doing some functions, I tried to create a project. I used the npm run build command for this. When I run this command, I can create a build folder.

Now I moved the build folder to my server and tried to execute. This gives me a blank white screen and says index.js was not found.

I am not sure how to solve this problem. Could you help me. thank.