Apex domains cannot have CNAME records.
Question and response
Question
dig sinersio.com. NS
Answer
sinersio.com. 1 NS ns2.sinersio.com.
sinersio.com. 1 NS ns3.sinersio.com.
sinersio.com. 1 NS ns1.sinersio.com.
Authority
The response has no authority records.
Additional
ns1.sinersio.com. 1 A 5.152.160.143
ns2.sinersio.com. 1 A 5.152.161.149
ns3.sinersio.com. 1 A 185.94.71.32
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0