widget not visible in sidebar

hello everybody,
following problem with the plugin: i added the widget to my sidebar and everything went fine. i subscribed with my own mailadress for testing and then removed it from the sidebar for a while. now i want to offer the service offically – but its not shown anymore at the website and i have no idea why.
i already deleted and installed new (my own subscription still works) but nothing changed. it appears in my sidebar in the dashboard but not at the website.
anyone who has an idea?

thanks

https://www.ads-software.com/plugins/subscribe-connect-follow-widget/