I tested this C# code snippet on Win 10:
NotifyIcon ni = new NotifyIcon();
ni.Icon = SystemIcons.Exclamation;
ni.Visible = true;
ni.ShowBalloonTip(1000, "title", "text", ToolTipIcon.Error);
It shows a permanent notifyicon in the taskbar and a temporary balloontip in the notifications area.
Without setting visibility nothing shows. Without setting icon nothing shows.
Translation to VB.NET should be straightforward. I did not test on Win 11.