shortcode not working

I created a group.

I created a testimonial.

I added the testimonial to the group.

When I hover the [shortcode] button on the Edit Group screen, I get
[a-excited-testimonials id="4"]

When I hover the [shortcode] button on the My Groups screen, I get
[a-excited-testimonials-free id="4"]

I added both to a page just to see. The ‘-free’ one is not rendered so the first one must be correct. But that doesn’t show anything.

Is there something else that needs to be set?

https://wordpress.org/plugins/excited-testimonials-showcase/