524 error was because I plugged wrong ipv6 ips. I removed them, but had to disable proxy because site have to be up.
Hosting itself is in Europe so I am pretty much sure that it’s up.
In short, I and website’s customers can’t just reach ips mentioned in subject. I read similar articles and seems to be Cloudflare’s issue - I can’t just say to every site visitor contact their ISP to diagnose and solve it 