Javascript signalr client poser

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C#

Javascript

I have a Net Core app which sends SignalR notifications when certain events occur, my client ( Web app ) captures these notifications using SignalR client C# handlers. All working perfectly. I would like to have a Javascript client which does the same thing because I need to manipulate the DOM - I downloaded some Javascript which connects to the server fine, but never receives any notifications - this is the code

document.addEventListener('DOMContentLoaded', function ()
{
    var connection = new signalR.HubConnectionBuilder()
        .withUrl("http://nuc:9653/pgnotify",
         {
            skipNegotiation: true,
            transport: signalR.HttpTransportType.WebSockets
        }).build();

    connection.on("PGNotify", function (message)
    {
        console.log("Notification received --> ", message);
    });

    async function start() {
        console.log("Starting SignalR client");
        await connection.start();
        console.log("SignalR connected");
    };
    start();
});

As I said earlier the code connects ok but never receives any notifications.
Any ideas guys ?

What I have tried:

What I show above and googling