_spf-ip.thruinc.com has no CNAME records.
Question and response
Question
dig _spf-ip.thruinc.com. NS
Answer
The response has no answer records.
Authority
thruinc.com. 496 SOA a1.uberns.com. admin.thruinc.com. 2602260001 14400 7200 259200 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0