Icons visible in editor, not visible on published posts

Hi there! I’m using the plugin and loving it but the icons I select don’t show up on my published page (for example: https://xsreviews.co.uk/editorial/games-with-built-in-benchmarks-2017/). I selected a shopping cart icon for these buttons, which shows up fine in my editor but then disappears in the published post. Any ideas what might be causing this? Anything I can check?

Cheers,

Will