Apex domains cannot have CNAME records.
Question and response
Question
dig 13.88.149.in-addr.arpa. NS
Answer
13.88.149.in-addr.arpa. 5 NS ns2.jotelulu.com.
13.88.149.in-addr.arpa. 5 NS ns3.jotelulu.com.
13.88.149.in-addr.arpa. 5 NS ns1.jotelulu.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0