Apex domains cannot have CNAME records.
Question and response
Question
dig thunderheartstudioinc.com. NS
Answer
thunderheartstudioinc.com. 5 NS ns2.thunderheartstudioinc.com.
thunderheartstudioinc.com. 5 NS ns1.thunderheartstudioinc.com.
Authority
The response has no authority records.
Additional
ns1.thunderheartstudioinc.com. 5 A 162.244.83.49
ns2.thunderheartstudioinc.com. 5 A 162.244.83.48
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0