It's a precaution, both against bots and users. I see you submitted another thread 8 minutes later so it works and was hopefully only a minor inconvienience.

Please stop posting threads and read the Guidelines and FAQ at the bottom of the window instead.

@anibrowl, thanks, I’ve noticed FAQ a bit later. It will be good if guidelines https://news.ycombinator.com/newsguidelines.html will have a link to https://news.ycombinator.com/newsfaq.html.

Also the error messages should be self-explainatory, at least has reference to appropriate section of FAQ. I searched for word “fast” and it wasn’t found. Is it related to delay or noprocrast settings?