For the last 2 days the fingerprints.bablosoft.com service was unavailable for users from Russia. It is now fixed. If the problem occurs again, a temporary solution is to use a VPN.
Technical details: As it turned out, RKN (Roskomnadzor) blocks some cloudflare addresses. 104.27.149.203 — here is an example of an ip on which their proxy runs. You can check it here https://blocklist.rkn.gov.ru/ I don't quite understand how it works, but apparently the block type "restricted to the site" means that a domain or some pages are blocked, but not the ip itself.
It also turned out that some addresses, and most likely whole networks, on digital ocean hosting are blocked. Apparently Telegram used them to bypass blocks.
I moved the bablosoft infrastructure to addresses that are not listed in the registry. The solution is not very elegant, but for now it's like this; if there are problems again, other options are possible.