Hi,
I think it was heavy firewall of Cloudflare set to high on both DDoS and firewall.
Google it’s a bot so maybe Cloudflare block all bots because after change setting to medium it start to crawler again.
Anyway Cloudflare was the only change before that happen, so I don’t know why but stop Google bot and give 403
Hope to have solve in this way because before everything working good.
I update till 2-3 days to tell that it’s true or not.
Enrico.