JavaScript Broadcastchannel eventlistener not triggering when posting message

I have the following html file. When I open it the console only shows “BroadcastChannel created …” and “Posting message to channel”. Neither the eventlistener nor the onmessage function triggers.

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>BroadcastChannel Simple Test</title>
</head>

<body>
    <script>
        // Create a BroadcastChannel
        const messageChannel = new BroadcastChannel('newMessageChannel');
        console.log("BroadcastChannel created:", messageChannel);

        // Set up the message event listener
        messageChannel.onmessage = (event) => {
            console.log("new message received on message!", event.data);
        };
        messageChannel.addEventListener('message', (event) => {
            console.log("new message received eventlistener!", event.data);
        });

        // Immediately post a message to the channel
        setTimeout(() => {
            console.log("Posting message to channel");
            messageChannel.postMessage("data");
        }, 1000);
    </script>
</body>

</html>


I tested it on two different machines in two different browsers.