Iframe Not Visible – Amazon Widget

My Amazon book widgets have disappeared on two websites. I don’t recall any recent updates being made to my sites.

When I use Inspect Element in Google Chrome, I can see the iframe code. When I click on the link, it opens the iframe child window on Amazon in a new tab, and I can see/click on the widget. This would indicate that the widget is working and there’s likely a conflict on my site. So, I deactivated all plugins except for iframe, and the widget is still hidden. As I said, I don’t recall making any changes to both of these sites that would have caused this.

Here’s an example of the problem –

https://99cent-books.com/the-god-complex/

The widget should be shown to the left of the table listing the book’s details.

Any thoughts?

Note: I reposted this b/c I had additional relevant details to add which the system wasn’t permitting me to do. If you delete one of these posts, please delete the first post and leave this one. Thanks

https://www.ads-software.com/plugins/iframe/