Apex domains cannot have CNAME records.
Question and response
Question
dig allportsshipping.com. NS
Answer
allportsshipping.com. 5 NS ns-1870.awsdns-41.co.uk.
allportsshipping.com. 5 NS ns-877.awsdns-45.net.
allportsshipping.com. 5 NS ns-425.awsdns-53.com.
allportsshipping.com. 5 NS ns-1342.awsdns-39.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0