It's in the early 1500s. Some of the early 5e adventure books set out a concrete date. Princes of the Apocalypse, for example, happens during the 1490s. Also, the novels, the video games, and the sourcebooks have never actually been on an entwined timeline, so the fact that the novel's aren't canon isn't news. I imagine that when the new tv series comes out it also will be on it's own timeline and won't really be canon for any of the others.
