Apex domains cannot have CNAME records.
Question and response
Question
dig volc-dns.net. NS
Answer
volc-dns.net. 4 NS ns-telecom.volc-dns.net.
volc-dns.net. 4 NS ns-mobile.volc-dns.net.
volc-dns.net. 4 NS ns1.volc-dns.net.
volc-dns.net. 4 NS ns2.volc-dns.net.
volc-dns.net. 4 NS ns-unicom.volc-dns.net.
Authority
The response has no authority records.
Additional
ns1.volc-dns.net. 4 A 8.129.10.141
ns1.volc-dns.net. 4 A 39.97.184.53
ns1.volc-dns.net. 4 A 47.103.144.65
ns2.volc-dns.net. 4 A 39.97.243.225
ns2.volc-dns.net. 4 A 47.103.69.110
ns2.volc-dns.net. 4 A 47.115.127.205
ns-mobile.volc-dns.net. 4 A 111.48.200.131
ns-unicom.volc-dns.net. 4 A 122.189.220.132
ns-telecom.volc-dns.net. 4 A 119.97.179.131
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0