Apex domains cannot have CNAME records.
Question and response
Question
dig 9.113.203.in-addr.arpa. NS
Answer
9.113.203.in-addr.arpa. 5 NS ns1.totbb.net.
9.113.203.in-addr.arpa. 5 NS ns2.totbb.net.
Authority
The response has no authority records.
Additional
ns1.totbb.net. 5 A 118.174.8.50
ns2.totbb.net. 5 A 118.174.11.130
ns1.totbb.net. 5 AAAA 2001:ec0:102:715:0:0:0:50
ns2.totbb.net. 5 AAAA 2001:ec0:120:1:0:0:0:130
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0