Apex domains cannot have CNAME records.
Question and response
Question
dig tbh.net. NS
Answer
tbh.net. 5 NS ns4.tbh.net.
tbh.net. 5 NS ns3.tbh.net.
Authority
The response has no authority records.
Additional
ns3.tbh.net. 5 A 199.212.118.7
ns4.tbh.net. 5 A 199.212.118.8
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0