Hello 
@Joaquin-Sanchez-Tona !
You need to make sure that the routing is set up correctly for both local development and when the site is deployed on Netlify. The most common cause for this issue is that the server-side routing is not set up properly in the deployed environment.
Netlify provides a “_redirects” file or a “netlify.toml” file to handle redirects and rewrites. Can you check and ensure you have configured the file correctly to handle your client-side routing? Make sure there are rules to redirect all requests to your main index.html file, where your React application will handle the routing.
For example, in your “_redirects” file or “netlify.toml” file, you’ll need to add the following rule:
/* /index.html 200
I recommend you take a look at this documentation:
This rule ensures that any request made to the server is redirected to the “index.html” file.