Apparently my shared hosting provider has issues with the Kiev Cloudflare data center. The result is that several visitors reported getting the following error message:
I don’t have control over the shared hosting, but the issue can be fixed if I can prevent Cloudflare from using the Kiev data center. Is that possible?
I can’t think of a way off the top of my head. Your Cloudflare IP address is geographically routed to the nearest Cloudflare datacenter. There’s nothing you can do from your account that can bypass this.
Can’t you ask your host to whitelist the Cloudflare IP addresses? This is bound to be a problem with anyone else at your host using Cloudflare who has Russian visitors.