Apex domains cannot have CNAME records.
Question and response
Question
dig hcvlny.alticeusa.net. NS
Answer
hcvlny.alticeusa.net. 5 NS authns1.cvnet.com.
hcvlny.alticeusa.net. 5 NS authns1.cv.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0