Welcome Bar Not Showing, Admin Preview Not Showing Either

I’ve installed the Welcome Bar WP plugin. The bar doesn’t show up on my pages, and in the admin settings, where it says, “Visitors from everywhere will see this bar at the top of their screen:” there’s nothing in the box. So it seems there is a problem. But I don’t know where to start. Any ideas? Thanks a lot!

Here’s my site. WB is activated (at least as of now): http://www.garthstein.com

https://wordpress.org/plugins/addthis-welcome/