Apex domains cannot have CNAME records.
Question and response
Question
dig bswift.com. NS
Answer
bswift.com. 4 NS ns-277.awsdns-34.com.
bswift.com. 4 NS ns-620.awsdns-13.net.
bswift.com. 4 NS ns-1428.awsdns-50.org.
bswift.com. 4 NS ns-1770.awsdns-29.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0