Apex domains cannot have CNAME records.
Question and response
Question
dig procusmart.com. NS
Answer
procusmart.com. 5 NS ns-1548.awsdns-01.co.uk.
procusmart.com. 5 NS ns-774.awsdns-32.net.
procusmart.com. 5 NS ns-133.awsdns-16.com.
procusmart.com. 5 NS ns-1132.awsdns-13.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0