Just for help:
In NodeJS, configure your httpserver with:
var privateKey = fs.readFileSync('path/to/your/private-key.pem'), 'utf8');
var certificate = fs.readFileSync('path/to/your/cert.pem', 'utf8');
// this is so important. Many tutorials forget to include chain.pem
var ca = fs.readFileSync('path/to/your/chain.pem', 'utf8');
var credentials = {
key: privateKey,
cert: certificate,
ca: ca
};
httpsServer = https.createServer(credentials, yourExpressInstance);