Amazon is phasing out the Product Display Ads for authors on the US site. I have an ad running on the UK site. I've not received a notice they're doing the same.
"We are retiring Product Display Ads for authors. As of January 7, 2019, you can no longer create new Product Display Ads. But you can continue to run and edit existing Product Display Ads through February 5, 2019. Your historical campaign data will remain accessible in the advertising console."
"Lockscreen Ads: Our newest ad type for authors provides you with many of the same benefits as Product Display Ads, plus new placements. Continue targeting by interest and reach readers actively reading on Kindle E-readers. Your ads can appear on Amazon Fire tablets in full-color display. "
I couldn't begin to tell you which ones I have set up where. Every single time I look at the Amazon ads, I have to re-educate myself on what they are and what they do (which is bugger all, in my case!)
"We are retiring Product Display Ads for authors. As of January 7, 2019, you can no longer create new Product Display Ads. But you can continue to run and edit existing Product Display Ads through February 5, 2019. Your historical campaign data will remain accessible in the advertising console."
"Lockscreen Ads: Our newest ad type for authors provides you with many of the same benefits as Product Display Ads, plus new placements. Continue targeting by interest and reach readers actively reading on Kindle E-readers. Your ads can appear on Amazon Fire tablets in full-color display. "