Apex domains cannot have CNAME records.
Question and response
Question
dig webportalpro.com. NS
Answer
webportalpro.com. 3 NS dn1.webportalpro.com.
webportalpro.com. 3 NS dn2.webportalpro.com.
Authority
The response has no authority records.
Additional
dn1.webportalpro.com. 3 A 5.135.87.70
dn2.webportalpro.com. 3 A 145.239.170.70
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0