Hi,
We have best-realty.ru domain in my account , and it seems to be not working from some Internet providers in Russia. We use proxied DNS. We try to do some settings without effect. And we have different domain umcashipping.ru that based on cloudflare NS too. And it works.
Difference between them only in NS servers
best-realty.ru has
nserver: melody.ns.cloudflare.com.
nserver: rudy.ns.cloudflare.com.
umcashipping.ru has
nserver: aria.ns.cloudflare.com.
nserver: trey.ns.cloudflare.com.
Maybe you can help and change NS? Or maybe we need to setup something different?