net::ERR_INSECURE_RESPONSE Angular 2 + Node.js + Socket.io - node.js

Question

I am developing a web app with Angular 2, Node.js and socket.io. It is working perfectly fine with http, however I wanted to implement https protocol and I hit the wall.
I am getting net::ERR_INSECURE_RESPONSE on any http call from angular to my web api and also when trying to make a socket connection.
Here is what I did:
1) Generated my private key and csr.
2) Requested SSL certificate from Comodo using that csr.
3) Received 2 files from Comodo:
- domain.ca-bundle
- domain.crt
4) I copied those 2 files and my private key to a folder: /etc/apache2/ssl/
5) I modified default-ssl.conf in etc/apache2/sites-available to point to these files:
SSLCertificateFile /etc/apache2/ssl/domain.crt
SSLCertificateKeyFile /etc/apache2/ssl/mypriv.key
SSLCertificateChainFile /etc/apache2/ssl/domain.ca-bundle
plus added:
ServerName domain.io
ServerAlias www.domain.io
6) Enabled https and restarted apache. Verified using SSL analyzer (https://sslanalyzer.comodoca.com/) if my cert is properly set up. It confirmed that connection to my site is now secure, so I assume this part was done properly and now I needed to fix the app and the server to handle https.
7) This is how socket connection is created in angular:
this.socket = io.connect('https://server_ip' + ':3000', {
rejectUnauthorized: false });
This is gonna give me net::ERR_INSECURE_RESPONSE later on
8) Angular app is also making http requests to the server like this:
var headers = new Headers();
headers.append('Content-Type', 'application/json');
let options = new RequestOptions({ headers: headers });
return this.http.post('https://server_ip' + ':3000/register',
JSON.stringify(userModel), options)
.map(res => res.json())
This is gonna give me net::ERR_INSECURE_RESPONSE as well (in response to OPTIONS call)
9) Now on the server side, this is the relevant piece of code:
var https = require('https');
var options = {
ca: splitca('/etc/apache2/ssl/domain.ca-bundle'),
key: fs.readFileSync('/etc/apache2/ssl/mypriv.key'),
cert: fs.readFileSync('/etc/apache2/ssl/domain.crt')
};
var server = https.createServer(options, app);
let io = require('socket.io')(https);
server.listen(3000, () => {
logger.debug('server started on port');
})
Server starts up fine, but any call from angular results in net::ERR_INSECURE_RESPONSE response (tried chrome, mozilla and IE). Both server and angular app are running on the same IP.
Any idea what I might be doing wrong here? Thanks!