An empty response comes when tests are performed

I am testing adding products, I want to add 10 products, but the problem is that I get an empty answer. I use the https://www.npmjs.com/package/multer library.

My test:

    describe('POST /api/products/add', () => {
        it(`Should create ${addProductCount} products with 0...1000 price`, (done) => {
            let operationCount = addProductCount;
            for (let i = 0; i < addProductCount; i++) {
                chai
                    .request(server)
                    .post('api/products/add')
                    .set('token', constants.merchantToken)
                    .field('product_name', 'test')
                    .field('product_description', 'description description')
                    .field('original_price', '20')
                    .field('sale_price', '10')
                    .field('starting_date', '2019-04-19T17:03:00+00:00')
                    .field('end_date', '2019-04-19T20:03:00+00:00')
                    .field('quantity_available', '20')
                    .field('quantity_available', 'HOME APPLIANCES')
                    .attach('product_photos', fs.readFileSync(images1), 'test1.jpeg')
                    .attach('product_photos', fs.readFileSync(images2), 'test2.jpg')
                    .attach('product_photos', fs.readFileSync(images3), 'test3.png')
                    .end((err, res) => {
                        operationCount--;
                        expect(res).have.status(200);
                        expect(res.body).have.property('message');
                        expect(res.body.message).to.be.equal('Product added');
                        if (operationCount == 0) {
                            done();
                        }
                    });
            }
        });
    });

When performing tests, I get an error:

Uncaught TypeError: Cannot use 'in' operator to search for 'status' in undefined
 at Proxy.<anonymous> (node_modules\chai-http\lib\http.js:80:38)
 at Proxy.methodWrapper >(node_modules\chai\lib\chai\utils\addMethod.js:57:25)
 at status (test/productsTest.js:73:42)
 at Test.Request.callback (node_modules\superagent\lib\node\index.js:728:3)
 at ClientRequest.req.once.err (node_modules\superagent\lib\node\index.js:647:10)
 at ClientRequest.EventEmitter.emit (domain.js:441:20)
 at Socket.socketErrorListener (_http_client.js:392:9)
 at Socket.EventEmitter.emit (domain.js:441:20)
 at emitErrorNT (internal/streams/destroy.js:82:8)
 at emitErrorAndCloseNT (internal/streams/destroy.js:50:3)
 at process._tickCallback (internal/process/next_tick.js:63:19)

When I do console.log(res) I get undefined

When I do console.log(err) I get:

{ Error: connect ECONNREFUSED 127.0.0.1:80
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1097:14)
  errno: 'ECONNREFUSED',
  code: 'ECONNREFUSED',
  syscall: 'connect',
  address: '127.0.0.1',
  port: 80,
  response: undefined }

Through the postman with this data, the product is added successfully. What is the problem of my test?