Apex domains cannot have CNAME records.
Question and response
Question
dig formassembly.com. NS
Answer
formassembly.com. 3 NS ns-1801.awsdns-33.co.uk.
formassembly.com. 3 NS ns-6.awsdns-00.com.
formassembly.com. 3 NS ns-683.awsdns-21.net.
formassembly.com. 3 NS ns-1443.awsdns-52.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0