firebase – Unable to retrieve data from firestore with flutter web app

I’m not able to retrieve data from cloud firestore using the flutter web app.
I can write data but cant read it.
In the app for android / ios it works fine with the emulator. I hope that someone can help me.

This is my index.html:

<!DOCTYPE html>
<html>
<head>
  <base href="/">

  <meta charset="UTF-8">
  <meta content="IE=Edge" http-equiv="X-UA-Compatible">
  <meta name="description" content="A new Flutter project.">

  <!-- iOS meta tags & icons -->
  <meta name="apple-mobile-web-app-capable" content="yes">
  <meta name="apple-mobile-web-app-status-bar-style" content="black">
  <meta name="apple-mobile-web-app-title" content="hsgaburg">
  <link rel="apple-touch-icon" href="icons/Icon-192.png">

  <!-- Favicon -->
  <link rel="icon" type="image/png" href="favicon.png"/>

  <title>test</title>
  <link rel="manifest" href="manifest.json">
</head>
<body>
 
  <script>
    if ('serviceWorker' in navigator) {
      window.addEventListener('flutter-first-frame', function () {
        navigator.serviceWorker.register('flutter_service_worker.js');
      });
    }
  </script>
 <script src="https://www.gstatic.com/firebasejs/8.2.7/firebase-app.js"></script> 

     <script src="https://www.gstatic.com/firebasejs/8.2.7/firebase-analytics.js"></script>
     <script src="https://www.gstatic.com/firebasejs/8.2.7/firebase-auth.js"></script>
     <script src="https://www.gstatic.com/firebasejs/8.2.7/firebase-firestore.js"></script>
     <script src="https://www.gstatic.com/firebasejs/8.2.7/firebase-functions.js"></script>
     <script src="https://www.gstatic.com/firebasejs/8.2.7/firebase-messaging.js"></script>  
<script>
  var firebaseConfig = {
    apiKey: "",
    authDomain: "",
    databaseURL: "",
    projectId: "",
    storageBucket: "",
    messagingSenderId: "",
    appId: ""
  };
  // Initialize Firebase
  firebase.initializeApp(firebaseConfig);
</script>  


  <script src="main.dart.js" type="application/javascript"></script>
</body>
</html>

With the StreamBuilder I want to retrieve the data:

 StreamBuilder<List<News>>(
      stream: newsBloc.getAllNews,
      builder: (context, snapshot) {
        if (!snapshot.hasData)
          return (UniversalPlatform.isIOS)
              ? CupertinoActivityIndicator()
              : CircularProgressIndicator();

        return Column(
          children: (
            Expanded(
              child: ListView.builder(
                itemCount: snapshot.data.length,
                itemBuilder: (context, index) {
                  return Container(
                    margin: EdgeInsets.all(10),
                    decoration: BoxDecoration(),
                    child: Bubble(
                      color: Colors.white,
                      elevation: 5,
                      margin: BubbleEdges.only(top: 10),
                      stick: true,
                      nip: BubbleNip.leftTop,
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: (
                          Text(
                            snapshot.data(index).creator,
                            style: TextStyles.headline3,
                          ),
                          AppDivider(),
                          Padding(
                            padding:
                                const EdgeInsets.symmetric(vertical: 10.0),
                            child: Text(snapshot.data(index).newsText,
                                style: TextStyles.body),
                          ),
                          Row(
                            mainAxisAlignment: MainAxisAlignment.end,
                            children: (
                              Text(
                                formatDate(snapshot.data(index).createdAt),
                                style: TextStyles.placeholder,
                              ),
                            ),
                          ),
                        ),
                      ),
                    ),
                  );
                },
              ),
            ),
          ),
        );

        /* } else
                return CircularProgressIndicator(); */
      })

Here is my pubspec.yaml:

  flutter:
    sdk: flutter
  http:
  firebase_messaging: ^8.0.0-dev.11
  groovin_widgets: ^1.6.0
  provider: ^4.3.2+2
  shared_preferences: ^0.5.12+4
  firebase_core: ^0.7.0
  cloud_firestore: ^0.16.0
  firebase_auth: ^0.20.0+1
  device_info: ^1.0.0
  package_info: ^0.4.3+2
  uuid: ^2.2.2
  google_fonts: ^1.1.1
  rxdart: ^0.25.0
  bubble: ^1.1.9+1
  intl: ^0.16.1
  table_calendar: ^2.3.3
  flutter_bloc: ^6.1.1
  numberpicker: ^1.3.0
  ##for web:
  universal_platform: ^0.1.3