Apex domains cannot have CNAME records.
Question and response
Question
dig kolam-jp.com. NS
Answer
kolam-jp.com. 4 NS ns-1292.awsdns-33.org.
kolam-jp.com. 4 NS ns-1721.awsdns-23.co.uk.
kolam-jp.com. 4 NS ns-980.awsdns-58.net.
kolam-jp.com. 4 NS ns-1605.awsdns-08.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0