Apex domains cannot have CNAME records.
Question and response
Question
dig staging.esaas.inmoment.com. NS
Answer
staging.esaas.inmoment.com. 2 NS ns-686.awsdns-21.net.
staging.esaas.inmoment.com. 2 NS ns-410.awsdns-51.com.
staging.esaas.inmoment.com. 2 NS ns-1827.awsdns-36.co.uk.
staging.esaas.inmoment.com. 2 NS ns-1284.awsdns-32.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0