Apex domains cannot have CNAME records.
Question and response
Question
dig ticketsnow.com. NS
Answer
ticketsnow.com. 4 NS ns-330.awsdns-41.com.
ticketsnow.com. 4 NS ns-1230.awsdns-25.org.
ticketsnow.com. 4 NS ns-709.awsdns-24.net.
ticketsnow.com. 4 NS ns-1714.awsdns-22.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0