当axios使用参数调用后，Express JS返回404

Question

我在一个存储库中有一些用于API的expressJS代码（返回），我想在我的路由'/ login'上使用axios在另一个存储库（ReactJS - Front）上进行POST调用，但它没有'工作并返回404错误代码。

App.js（API）：

const express = require('express');
const app = express()
const PORT = process.env.PORT || 3001
const bodyParser = require('body-parser')
const mysql = require('mysql');
const bdd = mysql.createConnection({
  host     : 'localhost',
  user     : 'root',
  password : 'root',
  database: 'football'
});

bdd.connect();


app.use(bodyParser.json());

app.use(bodyParser.urlencoded({
    extended: true
}));

// My other routes

//LOGIN
app.post('/login',(req,res)=>{
  const mail = req.body.mail
  const password = req.body.password
  bdd.query(`SELECT * FROM user WHERE mail = '${mail}' AND password = '${password}'`, function(err, row, field){
    res.send(row)
  })
})


app.use((req,res,next)=>{
  res.status(404);
  res.json({code:'NOT_FOUND',message:'Page not found'});
});

app.listen(PORT)

module.exports = app

App.js（Front）：

import React, { Component } from 'react';
import axios from 'axios';

class Login extends Component {

  constructor(props) {
    super(props);
    this.state = {
      mail: null,
      password: null
    };
  }

  login = () => {
    if(this.state.mail != null && this.state.password != null){
      axios.post('http://127.0.0.1:3001/login',{
        mail : this.state.mail,
        password : this.state.password
      }).then(res)=>{
        console.log(res);
      };
    }
  }

export default Login;