Apex domains cannot have CNAME records.
Question and response
Question
dig ucnlabext.com. NS
Answer
ucnlabext.com. 5 NS ena-innse01.dradev.lab.
ucnlabext.com. 5 NS enb-innse01.dradev.lab.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0