Apex domains cannot have CNAME records.
Question and response
Question
dig pinterest.com. NS
Answer
pinterest.com. 5 NS ns9.pinterest.com.
pinterest.com. 5 NS ns5.pinterest.com.
pinterest.com. 5 NS ns6.pinterest.com.
pinterest.com. 5 NS ns10.pinterest.com.
Authority
The response has no authority records.
Additional
ns5.pinterest.com. 5 A 198.51.44.9
ns6.pinterest.com. 5 A 198.51.45.9
ns9.pinterest.com. 5 A 162.159.1.250
ns10.pinterest.com. 5 A 162.159.0.254
ns5.pinterest.com. 5 AAAA 2620:4d:4000:6259:7:9:0:1
ns6.pinterest.com. 5 AAAA 2a00:edc0:6259:7:9:0:0:2
ns9.pinterest.com. 5 AAAA 2400:cb00:2049:1:0:0:a29f:1fa
ns10.pinterest.com. 5 AAAA 2400:cb00:2049:1:0:0:a29f:fe
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0