Apex domains cannot have CNAME records.
Question and response
Question
dig ibanksystems.com. NS
Answer
ibanksystems.com. 5 NS ns-1917.awsdns-47.co.uk.
ibanksystems.com. 5 NS ns-1500.awsdns-59.org.
ibanksystems.com. 5 NS ns-466.awsdns-58.com.
ibanksystems.com. 5 NS ns-1012.awsdns-62.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0