Node.jsでhttpsプロキシを立てcurlで繋ぐと、curl側でエラーが出てしまう

###前提・実現したいこと
HTTPSでクライアント及びgoogle.comに接続するLプロキシを書こうとしたのですが、デバッグとして以下のコマンドでcurlで繋ごうとしたところ、エラーが出てしまいます。

curl -v --proxy-insecure -x https://localhost -L http://google.com

###発生している問題・エラーメッセージ
curlには以下のようなエラーが出ました。

* Rebuilt URL to: http://google.com/
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 443 (#0)
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: none
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Client hello (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* Proxy certificate:
*  subject: //
*  start date: Oct  4 22:59:50 2017 GMT
*  expire date: Oct  4 22:59:50 2018 GMT
*  issuer: //
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
> GET http://google.com/ HTTP/1.1
> Host: google.com
> User-Agent: curl/7.56.0
> Accept: */*
> Proxy-Connection: Keep-Alive
> 
< HTTP/1.1 302 Found
< cache-control: private
< content-type: text/html; charset=UTF-8
< referrer-policy: no-referrer
< location: https://www.google.co.jp/?gfe_rd=cr&dcr=0&ei=SRrxWYrHMbHU8AeByq2ABg
< content-length: 272
< date: Wed, 25 Oct 2017 23:12:09 GMT
< alt-svc: quic=":443"; ma=2592000; v="39,38,37,35"
< connection: close
< 
* Closing connection 0
* TLSv1.2 (OUT), TLS alert, Client hello (1):
* Issue another request to this URL: 'https://www.google.co.jp/?gfe_rd=cr&dcr=0&ei=SRrxWYrHMbHU8AeByq2ABg'
* Hostname localhost was found in DNS cache
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 443 (#1)
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: none
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Client hello (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN, server accepted to use http/1.1
* Proxy certificate:
*  subject: //ここは隠します
*  start date: Oct  4 22:59:50 2017 GMT
*  expire date: Oct  4 22:59:50 2018 GMT
*  issuer: // ここは隠します
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
* allocate connect buffer!
* Establish HTTP proxy tunnel to www.google.co.jp:443
> CONNECT www.google.co.jp:443 HTTP/1.1
> Host: www.google.co.jp:443
> User-Agent: curl/7.56.0
> Proxy-Connection: Keep-Alive
> 
* Proxy CONNECT aborted
* CONNECT phase completed!
* Connection #1 to host localhost left intact
curl: (56) Proxy CONNECT aborted

###該当のソースコード

javascript
1var httpProxy = require('http-proxy');
2var fs = require('fs');
3
4var config = {
5  port: process.env['PORT'], // 443
6
7  ssl: {
8    key: fs.readFileSync(__dirname + process.env['SSL_KEY'], 'utf8'), // ssl key
9    cert: fs.readFileSync(__dirname + process.env['SSL_CERT'], 'utf8') // ssl cert
10  }
11};
12
13
14var proxy = httpProxy.createServer({
15    ssl: config.ssl,
16    target: 'https://google.com',
17    secure: true
18}).listen(config.port);
19
20
21proxy.on('proxyReq', function (proxyReq, req, res) {
22  console.log('proxyReq');
23});
24
25proxy.on('proxyRes', function(proxyRes, req, res) {
26  console.log('proxyRes');
27});
28
29console.log('Server running at https://localhost:' + config.port);