Apex domains cannot have CNAME records.
Question and response
Question
dig dns.ws. NS
Answer
dns.ws. 5 NS us3.dns.ws.
dns.ws. 5 NS ns2.dns.ws.
dns.ws. 5 NS ns5.dns.ws.
dns.ws. 5 NS nsp.dnsnode.net.
dns.ws. 5 NS nsu.dnsnode.net.
dns.ws. 5 NS europe1.dnsnode.net.
dns.ws. 5 NS us4.dns.ws.
Authority
The response has no authority records.
Additional
ns2.dns.ws. 5 A 64.70.19.80
ns5.dns.ws. 5 A 64.70.19.70
nsp.dnsnode.net. 1 A 194.58.198.32
us3.dns.ws. 5 A 64.70.78.70
us4.dns.ws. 5 A 64.70.78.80
nsp.dnsnode.net. 1 AAAA 2a01:3f1:3032:0:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0