ns6.pinterest.com has no CNAME records.
Question and response
Question
dig ns6.pinterest.com. NS
Answer
The response has no answer records.
Authority
pinterest.com. 1371 SOA ns5.pinterest.com. hostmaster.nsone.net. 1658264916 21600 3600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0