Apex domains cannot have CNAME records.
Question and response
Question
dig tildadns.com. NS
Answer
tildadns.com. 5 NS 162.159.27.221.
tildadns.com. 5 NS 162.159.26.196.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0