There are numerous reasons why a website may not be ranking. Google uses over 200 filters of sorts to determine the quality of a website. MOZ has a very credible chart on what these are which have been gathered from a wide variety of sources.
Some may be due to Google and other search engines abilities to read and review a website page by page, or robots.txt blocking, or website structuring that on call may allow a website's pages to not be shown before publishing often in editor mode. Or the entire website could be believed to be permanently moved due to a 301 / 302 rewrite use or misuse history by domain or by server's IP... These are just some common reasons.
But let's review what MOZ experience shows in the Infographic below.