Single Product Sidebars Don't Appear At All

I’ve searched the support area for any clues here. I found the information about the single-product sidebar only appearing on the left, so I reset the sidebar settings to be on the left, and this works on my self-styled product overview page which I used to replace “shop”: https://celebratingchrist.com/products/ and on the product category pages, but the single-product sidebar doesn’t show up at all on the single product pages. Have I missed a setting somewhere?