I have posted about my another problem that related to this problen.
So for some reason when I start my react app with npm start and then trying to start server at the same port using serve module serve -s build my main PC returns a warning as it should be.
PC
But when I do same thing with the same project on my laptop it doesn't returns any errors. Serve server starts above my npm start server, so browser returns data without websocket connection, that allows to use auto page updates. And if I end serve server I'm localhost:3000 returns data that npm start should return.
Laptop
If I do this in reversed order (start serve server and then npm start react noticing that 3000 port is busy.
Laptop Reversed order
So in other words my apps can't see that 3000 port is busy when I'm starting server using npm start
I think that there is some kind of create-react-app settings that i don't know.
