Initial delay of 10s - Githubissues

Whenever I call a website, the initial template loads immediately, the websocket connection kicks in about 10 seconds later, but then it works okay. It should be much faster. Any hint on what causes this delay ? The browser claims it initiated the connection but there is no answer.

My code is:

For the website

<!DOCTYPE html>
<html>
  <head>
    <title>EHZ Web Server</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
  </head>
  <body onload ="initWebSocket()" bgcolor="000000" >
    ...
  <script>

  function init() { 
    Socket = new WebSocket('ws://' + window.location.hostname + ':81/'); 
    Socket.onmessage = function(event) { processReceivedCommand(event); }; 
  } 

  function processReceivedCommand(event) { 
    var obj = JSON.parse(event.data); 
    var Power = obj.ehz;
    document.getElementById('ehz').innerHTML = Power;
    if (Power >0 ) {
        document.getElementById('ehzstyle').style.color="red"; 
    } else {
        document.getElementById('ehzstyle').style.color="green"; 
    }

    document.getElementById('erzeugung').innerHTML = obj.erzeugung;
    document.getElementById('hausverbrauch').innerHTML = obj.hausverbrauch;
    if (obj.SMS >0 ) {
       document.getElementById('SMS').innerHTML = obj.SMS;
    } else {
       document.getElementById('SMS').innerHTML = "&nbsp;";
    }
    console.log('received json ' + event);  
    } 
  window.onload = function(event) {init();}
</script>
</body>
</html>

globals:

    WebSocketsServer webSocket = WebSocketsServer(81);
    DNSServer dnsServer;
   WebServer server(80);

setup():

         server.on("/EHZ", HTTP_GET,[]() { handleEHZ(); });  
         webSocket.begin();  
         webSocket.onEvent(webSocketEvent);  
         MDNS.addService("http", "tcp", 80);
         MDNS.addService("ws", "tcp", 81);

I do not use the callback function. When I send data, I use

webSocket.broadcastTXT( s.c_str());

to send a JSON string.

Links2004 / arduinoWebSockets

Initial delay of 10s #770