title: Websocket Server in Node.js return RSV1 error when accessing from the phone APP
body: <p>In Node.js, I have implemented a WebSocket server which is used by a smartphone app. In some cases I got this kind of error (Invalid WebSocket frame: RSV1 must be clear):</p>
  
  <p><a href="https://i.stack.imgur.com/wznxa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wznxa.png" alt="enter image description here"></a></p>
  
  <p>This kind of application is running on many different servers across the world, but have the problem only with one instance. The app crashes randomly when using the communication between smartphones (Android or IOS) but it did not crash if I try to send messages over WebSocket using Java.</p>
  
  <p>Looking at the doc of WebSocket specification have found that: 
  <a href="https://i.stack.imgur.com/D3Jvh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/D3Jvh.png" alt="enter image description here"></a></p>
  
  <p>Currently, I can't find what could be wrong. Do you think it could be some "network set-up issue"? </p>
  
  <p>The libraries used for WebSocket in Node.js is ws 6.2.1.</p>
  
  <p>The service is running inside a docker using alpine:8 image. As I told I have a problem only in one environment in all other environments everything works fine. Any idea what else to check? </p>