Apex domains cannot have CNAME records.
Question and response
Question
dig vist.is. NS
Answer
vist.is. 5 NS ns-547.awsdns-04.net.
vist.is. 5 NS ns-2013.awsdns-59.co.uk.
vist.is. 5 NS ns-166.awsdns-20.com.
vist.is. 5 NS ns-1345.awsdns-40.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0