Apex domains cannot have CNAME records.
Question and response
Question
dig pernillesteenberg.com. NS
Answer
pernillesteenberg.com. 5 NS ns-1703.awsdns-20.co.uk.
pernillesteenberg.com. 5 NS ns-444.awsdns-55.com.
pernillesteenberg.com. 5 NS ns-1482.awsdns-57.org.
pernillesteenberg.com. 5 NS ns-2035.awsdns-62.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0