Essay:Got demonetized by YouTube?

"If you’re in the YouTube Partner Program, you can monetize with ads. This article aims to help you understand which individual videos on your channel are suitable for advertisers. Our policies apply to all portions of your content (video or live stream, thumbnail, title, description, and tags). Learn more about our best practices. Our systems don't always get it right, but you can request human review of decisions made by our automated systems."

Got it from a YouTube support page.