Request is presenting Cross-Origin request Blocked in app Reactjs

I am developing an application in React and previously created a restful API with node and express, in my api I added The cors module const cors = require('cors'); and added it at startup to allow the requests, until everything is right, the problem and when I move to the react application, where I also added the axios module const axios = require("axios"); to treat the requests made by the application and thus avoid Cross-Origin but still it returns me the even. When I make a query in another API the application can bring me the data, I do not know if the reason and because the two are running on the same machine.

I am grateful for the attention of everyone who can help me! :)

Excerpt Reactjs

 axios.get("http://localhost:3001/api/MarcodeContainers").then(function (resposta) {

        var teste = resposta.data;

        console.log(teste);

    });

Express nodejs bootstrap

const http = require('http');
const express = require('express');
const morgan = require('morgan');
const webServerConfig = require('../config/web-server.js');
const router = require('./router');
const cors = require('cors');

let httpServer;
function initialize() {
  return new Promise((resolve, reject) => {
    const app = express();
    app.use(cors());

    httpServer = http.createServer(app);

    app.use(morgan('combined'));
    app.use(express.json({
        reviver: reviveJson
    }));

    app.use('/api', router);

    httpServer.listen(webServerConfig.port)
        .on('listening', () => {
            console.log(`Web server ouvindo em localhost:${webServerConfig.port}`);

            resolve();
        })
        .on('error', err => {
            reject(err);
        });
});
}