Configure Favicon on mobile device

I’ve configured my vaadin app to use a custom favicon. It works on desktop but if I open the app from my mobile device (IPhone 12) and review the open tabs the favicon is not shown. What do I have to configure to solve this?

Currently my Application class implements AppShellConfigurator and overrides the configurePage method as follows:

  @Override
    public void configurePage(AppShellSettings settings) {
        AppShellConfigurator.super.configurePage(settings);
        settings.addFavIcon("icon", "icons/favicon.ico", "67x67");
    }