Apex domains cannot have CNAME records.
Question and response
Question
dig theportalcorp.com. NS
Answer
theportalcorp.com. 5 NS ns-850.awsdns-42.net.
theportalcorp.com. 5 NS ns-231.awsdns-28.com.
theportalcorp.com. 5 NS ns-42.awsdns-05.com.
theportalcorp.com. 5 NS ns-303.awsdns-37.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0