Apex domains cannot have CNAME records.
Question and response
Question
dig 80-95.218.36.138.in-addr.arpa. NS
Answer
80-95.218.36.138.in-addr.arpa. 5 NS ns-1587.awsdns-06.co.uk.
80-95.218.36.138.in-addr.arpa. 5 NS ns-1459.awsdns-54.org.
80-95.218.36.138.in-addr.arpa. 5 NS ns-486.awsdns-60.com.
80-95.218.36.138.in-addr.arpa. 5 NS ns-705.awsdns-24.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0