Apex domains cannot have CNAME records.
Question and response
Question
dig pigmc.com. NS
Answer
pigmc.com. 4 NS ns-1774.awsdns-29.co.uk.
pigmc.com. 4 NS ns-1204.awsdns-22.org.
pigmc.com. 4 NS ns-982.awsdns-58.net.
pigmc.com. 4 NS ns-1935.awsdns-49.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0