Apex domains cannot have CNAME records.
Question and response
Question
dig 80-95.40.172.209.in-addr.arpa. NS
Answer
80-95.40.172.209.in-addr.arpa. 5 NS nsm0.tckops.net.
80-95.40.172.209.in-addr.arpa. 5 NS nsm3.tckops.net.
80-95.40.172.209.in-addr.arpa. 5 NS nsm1.tckops.net.
80-95.40.172.209.in-addr.arpa. 5 NS nsm2.tckops.net.
80-95.40.172.209.in-addr.arpa. 5 NS nsm4.tckops.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0