Apex domains cannot have CNAME records.
Question and response
Question
dig g.ntpns.org. NS
Answer
g.ntpns.org. 5 NS i.ntpns.org.
g.ntpns.org. 5 NS c.ntpns.org.
g.ntpns.org. 5 NS a.ntpns.org.
g.ntpns.org. 5 NS h.ntpns.org.
g.ntpns.org. 5 NS f.ntpns.org.
g.ntpns.org. 5 NS e.ntpns.org.
g.ntpns.org. 5 NS d.ntpns.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0