Apex domains cannot have CNAME records.
Question and response
Question
dig fundamentum.com.ua. NS
Answer
fundamentum.com.ua. 5 NS nsc1.srv53.org.
fundamentum.com.ua. 5 NS nsa4.srv53.com.
fundamentum.com.ua. 5 NS nsd1.srv53.com.
fundamentum.com.ua. 5 NS nsd1.srv53.net.
fundamentum.com.ua. 5 NS nsa2.srv53.org.
fundamentum.com.ua. 5 NS nsc4.srv53.net.
fundamentum.com.ua. 5 NS nsb2.srv53.org.
fundamentum.com.ua. 5 NS nsa3.srv53.net.
fundamentum.com.ua. 5 NS nsd3.srv53.org.
fundamentum.com.ua. 5 NS nsb1.srv53.net.
fundamentum.com.ua. 5 NS nsb3.srv53.com.
fundamentum.com.ua. 5 NS nsc1.srv53.com.
Authority
The response has no authority records.
Additional
nsb1.srv53.net. 5 A 135.181.9.148
nsc1.srv53.com. 5 A 78.27.225.73
nsc1.srv53.org. 5 A 78.27.225.71
nsd1.srv53.com. 5 A 89.184.64.99
nsd1.srv53.net. 5 A 89.184.64.68
nsd3.srv53.org. 5 A 89.184.64.96
nsb1.srv53.net. 5 AAAA 2a01:4f9:4a:530c:181:9:148:2
nsc1.srv53.com. 5 AAAA 2a02:2279:0:1201:78:27:225:73
nsc1.srv53.org. 5 AAAA 2a02:2279:0:1201:78:27:225:71
nsd1.srv53.com. 5 AAAA 2a02:2278:70eb:298:89:184:64:99
nsd1.srv53.net. 5 AAAA 2a02:2278:70eb:298:89:184:64:68
nsd3.srv53.org. 5 AAAA 2a02:2278:70eb:298:89:184:64:96
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0