March 14, Amazon wrote to me:

During our review process, we found that the subject matter of your book “Who did 9/11? A View from Across the Pond’? (ASIN B07F96SQDW)” is in violation of our content guidelines

I wrote to them pointing out that no other 9/11 truth book had been banned by them, and could they explain more? They replied:

Books  submitted through KDP   need to comply with our content guidelines, which apply to the book interior, cover image, and or product descriptions. 
We reserve the right to determine if a content provides a poor customer experience and remove that content from sale. We’re unable to elaborate further on specific details regarding our content guidelines

The book was up for several months as a Kindle book and then for one month as a paperback, before being banned.

My first book banned by Amazon was ‘Breaking the Spell’ https://holocausthandbooks.com/index.php?page_id=31