_spf.questback.com has no CNAME records.
Question and response
Question
dig _spf.questback.com. NS
Answer
The response has no answer records.
Authority
questback.com. 3095 SOA ns1.dnshost.net. zonemaster\@dnshost.net. 1771488418 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0