Access to XMLHttpRequest at 'https://fmc-library.herokuapp.com/api/auth/register' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. code example
Example 1: what is cors
“CORS” stands for Cross-Origin Resource Sharing.
It allows you to make requests from one website to another website
in the browser, which is normally prohibited by another browser policy
called the Same-Origin Policy (SOP).
Example 2: how to use cros
app.use not app.us