The hosting provider now says that these IP’s are being blocked by ISP on the basis of a court decision:
23.15.14.24 (because of this url: http://www.fun88.com/en-US/Home)
188.43.76.81 (unknown reason)
188.43.76.66 (unknown reason)
The oscp-servers are resolved to these IP’s (on my server). So, when I set up other IP (88.221.132.150) in my hosts file, the curl started to work. But nginx not, I think it doesn’t use hosts file.
The server and ISP are in the Russian jurisdiction. So it would be great if someone told LE, maybe they will stop using those IP’s.