The site was under a DDoS attack yesterday. That might have something to do with it.
Viewing post in Suddenly getting 429 Too Many Requests?
ddos counter measures can have longer side effects. And when I say that 429 does happen occasionally without ddos, read that as: it happened but I did not notice any ddos statement. Might as well have been a ddos every time. But what is a ddos? It is literally what the error message says. Too many requests. That can happen for other reasons as well. Like when there is a sale or some games get viral or whatever.