I'm trying to use express in conjunction with a node.js https server, but I'm getting a warning when I connect.

My code is:
var WebSocketServer = require('ws').Server
, https = require('https')
, fs = require('fs')
, express = require('express')
, app = express();
app.use(express.static(__dirname + '/public'));
var options = {
rejectUnauthorized: false,
requestCert: true,
agent: false,
key: fs.readFileSync('private/key.pem'),
cert: fs.readFileSync('private/cert.pem')
};
var server = https.createServer(options, app);
server.listen(8888);
var MainServer = new WebSocketServer({server: server});
How do I fix this warning (and effectively the Identity not verified problem)?
Thanks!