Apex domains cannot have CNAME records.
Question and response
Question
dig uadns.com. NS
Answer
uadns.com. 5 NS ns3.uadns.com.
uadns.com. 5 NS ns2.uadns.com.
uadns.com. 5 NS ns1.uadns.com.
Authority
The response has no authority records.
Additional
ns1.uadns.com. 5 A 178.62.201.147
ns2.uadns.com. 5 A 157.90.171.155
ns3.uadns.com. 5 A 195.149.114.23
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0