Apex domains cannot have CNAME records.
Question and response
Question
dig ip-51-79-19.net. NS
Answer
ip-51-79-19.net. 3 NS ns10.ovh.ca.
ip-51-79-19.net. 3 NS dns10.ovh.ca.
Authority
The response has no authority records.
Additional
ns10.ovh.ca. 1 A 167.114.154.30
dns10.ovh.ca. 1 A 192.99.60.247
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0