http://localhost:8080/ gives Whitelabel Error Page

[Chichiboof]

When i creat the production build i rebuild my server and nothing appear on localhost:8080 just the Error page

Whitelabel Error Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.

Wed Oct 11 10:38:38 CET 2017
There was an unexpected error (type=Not Found, status=404).
No message available

But i see the iconefav of react on the page title.

Then i tried the :
npm install -g serve and
the serve -s build gives me http://localhost:5000
When i lunch the spring boot server the http://localhost:5000 link is working but not 8080 port ?
And the button gives me on the console ERR_CONNECTION_REFUSED
Is it normal !!