o1.ptr5628.useworkshop.com has no CNAME records.
Question and response
Question
dig o1.ptr5628.useworkshop.com. NS
Answer
The response has no answer records.
Authority
useworkshop.com. 545 SOA cesar.ns.cloudflare.com. dns.cloudflare.com. 2397021267 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0