ns4.f5cloudservices.com has no CNAME records.
Question and response
Question
dig ns4.f5cloudservices.com. NS
Answer
The response has no answer records.
Authority
f5cloudservices.com. 1413 SOA ns1.f5clouddns.com. dns-admin\@f5cloudservices.com. 2023020907 86400 7200 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0