Apex domains cannot have CNAME records.
Question and response
Question
dig simac.com. NS
Answer
simac.com. 3 NS ns1.premium-dns.net.
simac.com. 3 NS ns2.premium-dns.net.
Authority
The response has no authority records.
Additional
ns1.premium-dns.net. 3 A 192.174.68.15
ns2.premium-dns.net. 3 A 176.97.158.15
ns1.premium-dns.net. 3 AAAA 2001:67c:1bc:0:0:0:0:15
ns2.premium-dns.net. 3 AAAA 2001:67c:10b8:0:0:0:0:15
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0