Suppose that I've an API that publishes a post in my Facebook account. What HTTP code should I return if the user hasn't linked yet his FB account with my API server (it's just an example)? I found "412 Precondition Failed" but I think that this is not the right use case. So what is the best HTTP code for telling that you should do an action first?
EDIT: just to help who will read this post; I've found a nice article that helps to choose the right HTTP status code. https://www.loggly.com/blog/http-status-code-diagram/