尝试获取 version 返回BadGatewayError错误

**通过`tws.get('/version')`获取版本信息，返回如下错误：**

````
BadGatewayError: <html>
<head><title>502 Bad Gateway</title></head>
<body>
<center><h1>502 Bad Gateway</h1></center>
<hr><center>nginx</center>
</body>
</html>
```