Apex domains cannot have CNAME records.
Question and response
Question
dig tellurian.net. NS
Answer
tellurian.net. 4 NS authns2.planet.net.
tellurian.net. 4 NS authns1.planet.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0