SignalR connection works with console app but not with ReactJS

I have the following relevant code on my ASP.NET server:

// TrackingHub.cs
public class TrackingHub : Hub
{
    public async Task SendLocationData(LocationData locationData)
    {
        await Clients.Others.SendAsync("ReceiveLocationData", locationData);
        Console.WriteLine($"{locationData.Latitude}, {locationData.Longitude}");
    }
}

// Program.cs
builder.Services.AddSignalR()
builder.Services.AddCors(options =>
{
    options.AddDefaultPolicy(builder =>
    {
        builder.WithOrigins("http://localhost:3000").AllowAnyHeader().AllowAnyMethod().AllowCredentials();
    });
});

//app.UseHttpsRedirection();
app.UseCors();
app.MapHub<TrackingHub>("/tracking");

Now on my .NET console app, I have the following relevant code. It works well and I receive the location data from it on my asp.net server:

HubConnection? hubConnection = new HubConnectionBuilder()
     .WithUrl("http://localhost:5191/tracking")
     .Build();

// stuff...
if (hubConnection != null)
{
    await hubConnection.SendAsync("SendLocationData", locationData);
}

And finally, this is the code I have on my react (NextJS) app:

const page = () => {
    const connection = new HubConnectionBuilder()
        .withUrl('http://localhost:5191/tracking')
        .withAutomaticReconnect()
        .build()

    connection.on('ReceiveLocationData', (locationData) => {
        console.log(locationData)
    });

    useEffect(() => {
        const startConnection = async () => {
            try {
                await connection.start()
            }
            catch (error) {
                console.log("Failed to start connection: ", error)
            }
        }

        startConnection()
    }, []);

    return (
        <Map />
    )
}

The connection, however, is not working with the React app. Note that other connections from the react app to the server work just fine (like regular GET or POST methods). I also checked the transport type being used by the working console app to see if websocket protocol is even functional or supported, and it was indeed using Websockets, which I checked using [https://stackoverflow.com/questions/49473648/determine-transport-method-in-signalr-core].

Here is an image of what I am getting on the console: