Apex domains cannot have CNAME records.
Question and response
Question
dig g-cloud.by. NS
Answer
g-cloud.by. 5 NS ns4.g-cloud.by.
g-cloud.by. 5 NS ns6.g-cloud.by.
g-cloud.by. 5 NS ns2.g-cloud.by.
g-cloud.by. 5 NS ns1.g-cloud.by.
g-cloud.by. 5 NS ns3.g-cloud.by.
g-cloud.by. 5 NS ns5.g-cloud.by.
Authority
The response has no authority records.
Additional
ns1.g-cloud.by. 5 A 195.50.4.201
ns2.g-cloud.by. 5 A 185.11.78.243
ns3.g-cloud.by. 5 A 31.40.200.164
ns4.g-cloud.by. 5 A 5.252.33.104
ns5.g-cloud.by. 5 A 93.125.24.195
ns6.g-cloud.by. 5 A 193.232.80.53
ns2.g-cloud.by. 5 AAAA 2a02:e300:0:21b:0:0:0:243
ns3.g-cloud.by. 5 AAAA 2a01:ba80:e:40:0:0:0:4
ns4.g-cloud.by. 5 AAAA 2a0e:b81:8001:1003:0:0:0:2
ns5.g-cloud.by. 5 AAAA 2a00:c827:6:6:0:0:0:5
ns6.g-cloud.by. 5 AAAA 2001:6d0:6d01:0:193:232:80:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0