Apex domains cannot have CNAME records.
Question and response
Question
dig istanapromo.com. NS
Answer
istanapromo.com. 5 NS ns-141.awsdns-17.com.
istanapromo.com. 5 NS ns-679.awsdns-20.net.
istanapromo.com. 5 NS ns-1051.awsdns-03.org.
istanapromo.com. 5 NS ns-1282.awsdns-32.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0