msa.lab.validsender.com has no CNAME records.
Question and response
Question
dig msa.lab.validsender.com. NS
Answer
The response has no answer records.
Authority
validsender.com. 1566 SOA kim.ns.cloudflare.com. dns.cloudflare.com. 2397109283 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0