Run the following block of code to test your environment

tls.js

var https = require("https");
var req = https.request({
 host: "preview.opentok.com",
 port: "443",
 path: "tls-check.json",
 method: "GET",
}, function (res) {
 res.on("data", function (data) {
   console.log("Connection successfully established with your current TLS configuration, no further action required.");
 });
});
req.end();
req.on("error", function(err) {
 if (err.code == "ECONNRESET") {
   console.log("Failed to connect to OpenTok, please check your system and upgrade your environment as needed.");
 } else {
   console.log("Unknown error talking to OpenTok, please try again later.");
 }
});

Hey preview.opentok.com no longer exists.