bas1.b2cdistribution.com has no CNAME records.
Question and response
Question
dig bas1.b2cdistribution.com. NS
Answer
The response has no answer records.
Authority
b2cdistribution.com. 1707 SOA lex.ns.cloudflare.com. dns.cloudflare.com. 2396720742 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0