Apex domains cannot have CNAME records.
Question and response
Question
dig riyadh-constructions.org. NS
Answer
riyadh-constructions.org. 1 NS ns-69.awsdns-08.com.
riyadh-constructions.org. 1 NS ns-1322.awsdns-37.org.
riyadh-constructions.org. 1 NS ns-801.awsdns-36.net.
riyadh-constructions.org. 1 NS ns-2035.awsdns-62.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0