Apex domains cannot have CNAME records.
Question and response
Question
dig transitsandiego.com. NS
Answer
transitsandiego.com. 5 NS ns-1562.awsdns-03.co.uk.
transitsandiego.com. 5 NS ns-1492.awsdns-58.org.
transitsandiego.com. 5 NS ns-668.awsdns-19.net.
transitsandiego.com. 5 NS ns-1734.awsdns-24.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0