Only the talented one known what this mean

General Discussion
1

[mod edit in order to show the html posted]

<!-- Copyright 2007-2009 Google Inc. All Rights Reserved. -->
<!-- Copyright 2011-2020 Massachusetts Institute of Technology. All Rights Reserved. -->
<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="X-UA-Compatible" content="IE=10">
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <!--meta name="gwt:property" content="locale=en_US"-->
    <!-- Title is set at runtime. -->
    <title> </title>
    <!-- Google Analytics. -->
    <!-- Google tag (gtag.js) -->
    <script async src="https://www.googletagmanager.com/gtag/js?id=G-0CGMHKLWBP"></script>
    <script>
      window.dataLayer = window.dataLayer || [];
      function gtag(){dataLayer.push(arguments);}
      gtag('js', new Date());

      gtag('config', 'G-0CGMHKLWBP');
    </script>
    <link type="text/css" rel="stylesheet" href="static/css/gwt.css">
    <link type="text/css" rel="stylesheet" href="static/css/blockly.css">
    <link type="text/css" rel="stylesheet" href="static/css/ai2blockly.css">
    <link type="text/css" rel="stylesheet" href="static/closure-library/closure/goog/css/dialog.css">
    <link type="text/css" rel="stylesheet" href="static/closure-library/closure/goog/css/hsvapalette.css">
    <link type="text/css" rel="stylesheet" href="static/font-awesome/css/font-awesome.min.css">
    <link type="text/css" rel="stylesheet" href="static/leaflet/leaflet.css">
    <link type="text/css" rel="stylesheet" href="static/leaflet/leaflet.toolbar.css">
    <link type="text/css" rel="stylesheet" href="static/leaflet/leaflet-vector-markers.css">
    <link type="text/css" rel="stylesheet" href="static/css/Ya.css">
    <link type="text/css" rel="stylesheet" href="static/css/android_holo.css">
    <link type="text/css" rel="stylesheet" href="static/css/android_material.css">
    <link type="text/css" rel="stylesheet" href="static/css/iOS.css">
    <link type="text/css" rel="stylesheet" href="static/css/DarkTheme.css">
    <noscript>
      <div class="floatingBox">
        <h2> App Inventor needs JavaScript enabled to run.</h2>
      </div>
    </noscript>
  </head>
  <!-- ODE scripts -->
  <body class="gwt-bodyRob">
    <div class="floatingBox" style="display:none" id="unsupported">
      <h2> Your browser might not be compatible. </h2>
      To use App Inventor, you must use a compatible browser.<br>
      Currently the supported browsers are:
      <ul>
        <li> Google Chrome 55+ </li>
        <li> Safari 11+ </li>
        <li> Firefox 52+ </li>
      </ul>
    </div>
    <script type="text/javascript" src="static/closure-library/closure/goog/base.js"></script>
    <script type="text/javascript" src="ode/ode.nocache.js"></script>
    <script src="static/leaflet/leaflet.js"></script>
    <script src="static/leaflet/leaflet.toolbar.js"></script>
    <script src="static/leaflet/leaflet-vector-markers.min.js"></script>
    <script src="static/leaflet/leaflet-imgicon.js"></script>
    <script src="static/leaflet/Path.Drag.js"></script>
    <script src="static/leaflet/Leaflet.Editable.js"></script>
    <script src="static/leaflet/leaflet.geometryutil.js"></script>
    <script src="static/leaflet/leaflet.snap.js"></script>
    <script>
      if (window.navigator.userAgent.indexOf("MSIE") != -1){
          document.getElementById("unsupported").style.display = 'block';
      }
    </script>
  </body>
</html>
2
3
4

You need to explain what your issue is?

5

This states that you need a java capable browser. It also tells you that there are three browsers which can be used, namely google chrome , safari, and firefox

6

So, which one are you using?

7

chrome