Co-Authors Plus not working

Hello, I’ve tried to get a second author to display on posts using Co-authors Plus, but while I can add more authors in the back end, no author other than the first is displayed in the post itself or in blocks where the post appears. Tried looking at your documentation here: https://forum.tagdiv.com/adding-multiple-authors-articles/ but it isn’t very helpful because all it says is “add a plugin” which I’ve done but it doesn’t provide guidance if it doesn’t work.

I’m not using Tag-Div cloud templates, just the standard theme template for posts, if that helps.

Any ideas welcome.