What is wrong with fetch?

Question

JavaScript

Hello. I understand AJAX requests. Faced such a problem.
There is such a function on node:

module.exports = function(app, db) {
    app.post('/notes', (req, res) => {
        // Здесь будем создавать заметку.
        res.send('Hello');
        console.log('answer sended');
    });
};

I'm trying to fetch this address:

As a result, I get an error:

Why does it occur? What am I doing wrong?

Answer 1

Memorize https://developer.mozilla.org/ru/docs/Web/HTTP/CORS