warning sockjs.js:2998 WebSocket connection to failed: WebSocket is closed before the connection is established

Question

I am having a Angular 8 front end code. When built it shows following error in browser console.

Getting warning sockjs.js:2998 WebSocket connection to 'ws://localhost:4200/sockjs-node/173/ypgvodsj/websocket' failed: WebSocket is closed before the connection is established.

WebSocketTransport.prototype.close = function() 
 {
  debug('close');
  var ws = this.ws;
  this._cleanup();
  if (ws) 
{
    ws.close();
 }
};