问Nodejs深流连接失败

EN

const express = require('express'),
  bodyParser = require('body-parser'),
  ds = require('deepstream.io-client-js'),
  app = express();

 // Create deepstream client
 const client = ds('wss://154.deepstreamhub.com?apiKey=xxx');
 client.login();  

 Error: connectionError: Error: self signed certificate in certificate chain (C)
at Client._$onError (C:\Users\xdidemk\Desktop\nodejs\node_modules\deepstream.io-client-js\dist\lib\client.js:204:11)
at Timeout._onTimeout (C:\Users\xdidemk\Desktop\nodejs\node_modules\deepstream.io-client-js\dist\lib\message\connect
 ion.js:315:19)
at ontimeout (timers.js:386:14)
at tryOnTimeout (timers.js:250:5)
at Timer.listOnTimeout (timers.js:214:5)