Apex domains cannot have CNAME records.
Question and response
Question
dig trdns.com. NS
Answer
trdns.com. 1 NS ns11.trdns.com.
trdns.com. 1 NS ns12.trdns.com.
Authority
The response has no authority records.
Additional
ns11.trdns.com. 1 A 77.245.148.3
ns12.trdns.com. 1 A 104.247.178.103
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0