Possibly incompatible – seeing 404 instead

I installed the plugin, then went to the configuration and was able to configure the plug-in. Tried not installing the PHP on every page as per instructions, and only adding the shortcode. That process seemed to work fine, the button appears and shows the text print. But when I click it, it tries to visit <domain>/<path/to/post>/post/print

Since /print is not a valid page, I assume this is something the plugin should fix, but instead it shows 404.