Apex domains cannot have CNAME records.
Question and response
Question
dig 0-24.202.110.124.in-addr.arpa. NS
Answer
0-24.202.110.124.in-addr.arpa. 5 NS ns-834.awsdns-40.net.
0-24.202.110.124.in-addr.arpa. 5 NS ns-1073.awsdns-06.org.
0-24.202.110.124.in-addr.arpa. 5 NS ns-1539.awsdns-00.co.uk.
0-24.202.110.124.in-addr.arpa. 5 NS ns-187.awsdns-23.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0