Apex domains cannot have CNAME records.
Question and response
Question
dig exhort.digital. NS
Answer
exhort.digital. 5 NS ns-1006.awsdns-61.net.
exhort.digital. 5 NS ns-919.awsdns-50.net.
exhort.digital. 5 NS ns-461.awsdns-57.com.
exhort.digital. 5 NS ns-1204.awsdns-22.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0