Apex domains cannot have CNAME records.
Question and response
Question
dig for.msk.ru. NS
Answer
for.msk.ru. 5 NS troy.ns.cloudflare.com.
for.msk.ru. 5 NS zelda.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
troy.ns.cloudflare.com. 2 A 108.162.195.218
troy.ns.cloudflare.com. 2 A 162.159.44.218
troy.ns.cloudflare.com. 2 A 172.64.35.218
zelda.ns.cloudflare.com. 2 A 108.162.192.242
zelda.ns.cloudflare.com. 2 A 172.64.32.242
zelda.ns.cloudflare.com. 2 A 173.245.58.242
troy.ns.cloudflare.com. 2 AAAA 2606:4700:58:0:0:0:a29f:2cda
troy.ns.cloudflare.com. 2 AAAA 2803:f800:50:0:0:0:6ca2:c3da
troy.ns.cloudflare.com. 2 AAAA 2a06:98c1:50:0:0:0:ac40:23da
zelda.ns.cloudflare.com. 2 AAAA 2606:4700:50:0:0:0:adf5:3af2
zelda.ns.cloudflare.com. 2 AAAA 2803:f800:50:0:0:0:6ca2:c0f2
zelda.ns.cloudflare.com. 2 AAAA 2a06:98c1:50:0:0:0:ac40:20f2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0