The Amazon kiss of death...
Ever heard of the Amazon Adult Filter? It's when Amazon hides your book into the tiniest corner of their site. If someone searches for your book, it won't even show up. The only way for someone to find your banished book is to open your author page and scroll through your titles and find it.
This video discusses how books end up getting flagged with the Adult Filter, what you can do to prevent your book from being flagged, and how to fix the situation if it does occur.
Links mentioned in the video:
Check your book's status at www.SalesRankExpress.com
If it shows up with the ADULT tag, and you think the cover is the issue, then change the cover, then email email@example.com and let them know that you've fixed the problem, and ask them to reconsider the title and remove the adult filter. If you aren't sure what the issue is, you can use the same email address and ask them if you can have information on why the book was filtered.