Apex domains cannot have CNAME records.
Question and response
Question
dig ntppool.org. NS
Answer
ntppool.org. 5 NS ns1.us.bitnames.com.
ntppool.org. 5 NS ns1.eu.bitnames.com.
ntppool.org. 5 NS ns3.us.bitnames.com.
ntppool.org. 5 NS ns2.us.bitnames.com.
ntppool.org. 5 NS anyns.pch.net.
Authority
The response has no authority records.
Additional
ns1.eu.bitnames.com. 5 A 165.227.133.206
ns1.us.bitnames.com. 5 A 178.128.191.122
ns2.us.bitnames.com. 5 A 107.170.182.174
anyns.pch.net. 3 A 204.61.216.4
ns1.eu.bitnames.com. 5 AAAA 2a03:b0c0:3:d0:0:0:c0:4001
ns1.us.bitnames.com. 5 AAAA 2604:a880:2:d0:0:0:1ce8:7001
anyns.pch.net. 3 AAAA 2001:500:14:6004:ad:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0