Apex domains cannot have CNAME records.
Question and response
Question
dig static.comm.cgocable.net. NS
Answer
static.comm.cgocable.net. 5 NS vader.cogeco.net.
static.comm.cgocable.net. 5 NS maul.cogeco.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0