Apex domains cannot have CNAME records.
Question and response
Question
dig us-us-citruna.com. NS
Answer
us-us-citruna.com. 5 NS ns1.us-us-citruna.com.
us-us-citruna.com. 5 NS ns2.us-us-citruna.com.
Authority
The response has no authority records.
Additional
ns1.us-us-citruna.com. 5 A 192.227.72.160
ns2.us-us-citruna.com. 5 A 192.227.72.164
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0