Pinterest button doesn't show

I want to add the Pinterest button, but when I enable it, the button doesn’t show. I can click the space where the button should be and I’m shown all images on the page to pin.
But the button is invisible.

I’ve tried to manually add the code to a post and auto-add it and it’s the same result. I’m in Chrome on a Mac by the way.

I also can’t figure out how to get it to directly pin the post’s featured image instead of showing all images.

https://www.ads-software.com/plugins/really-simple-facebook-twitter-share-buttons/