Apex domains cannot have CNAME records.
Question and response
Question
dig 176-28.175.210.62.in-addr.arpa. NS
Answer
176-28.175.210.62.in-addr.arpa. 5 NS ns1.levelsys.com.
176-28.175.210.62.in-addr.arpa. 5 NS ns2.levelsys.com.
176-28.175.210.62.in-addr.arpa. 5 NS ns0.levelsys.com.
Authority
The response has no authority records.
Additional
ns0.levelsys.com. 5 A 185.58.8.5
ns1.levelsys.com. 5 A 185.58.8.6
ns2.levelsys.com. 5 A 195.154.114.46
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0