Apex domains cannot have CNAME records.
Question and response
Question
dig 223.197.168.in-addr.arpa. NS
Answer
223.197.168.in-addr.arpa. 4 NS ns2.conectja.com.
223.197.168.in-addr.arpa. 4 NS ns1.conectja.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0