Apex domains cannot have CNAME records.
Question and response
Question
dig nas.net. NS
Answer
nas.net. 5 NS nsat.dns.nas.net.
nas.net. 5 NS nsah.dns.nas.net.
Authority
The response has no authority records.
Additional
nsah.dns.nas.net. 5 A 216.145.110.22
nsat.dns.nas.net. 5 A 216.145.109.5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0