Apex domains cannot have CNAME records.
Question and response
Question
dig nameshield.net. NS
Answer
nameshield.net. 5 NS nsc.perf1.com.
nameshield.net. 5 NS nsa.perf1.fr.
nameshield.net. 5 NS nsb.perf1.com.
nameshield.net. 5 NS nsz.perf1.com.
nameshield.net. 5 NS nsz.perf1.fr.
Authority
The response has no authority records.
Additional
nsa.perf1.fr. 5 A 81.92.94.100
nsb.perf1.com. 5 A 81.92.95.100
nsc.perf1.com. 5 A 152.89.172.100
nsz.perf1.fr. 5 A 208.80.126.13
nsz.perf1.com. 5 A 208.80.124.13
nsa.perf1.fr. 5 AAAA 2a01:c8:100:0:0:0:0:100
nsb.perf1.com. 5 AAAA 2a01:c8:101:0:0:0:0:100
nsc.perf1.com. 5 AAAA 2a09:35c0:102:0:0:0:0:100
nsz.perf1.fr. 5 AAAA 2600:1802:7:0:0:0:0:1
nsz.perf1.com. 5 AAAA 2600:1801:6:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0