节点CORS软件包不起作用

Question

I've inserted the following lines into my code:

var express = require('express');
var cors = require('cors');

var app = express();

app.options('*', cors());
app.use(cors());

However, when I make an AJAX POST request, I still get the error:

POST https://stormy-plateau-94715.herokuapp.com/login 
new-page-5:1 XMLHttpRequest cannot load https://stormy-plateau-94715.herokuapp.com/login. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://squareguru.squarespace.com' is therefore not allowed access. The response had HTTP status code 503.

This is my first time using the cors package, am I configuring something wrong? I would love any help you guys can give me, thanks!

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