Cover on the Kindle is the Calibre Logo

I have a MOBI in my Calibre library which shows with the book's actual cover.
When I open it in the eBook viewer the cover is the default Calibre generated one. That's also what I see in my Kindle's library when I copy the file over.

However, when I open the book editor there is a single item under "Images" and it's correct (the actual cover).

How can I get the cover to show on my Kindle?