mordred.membrane.com has no CNAME records.
Question and response
Question
dig mordred.membrane.com. NS
Answer
The response has no answer records.
Authority
membrane.com. 3390 SOA parsifal.membrane.com. sidd.membrane.com. 2025090700 10800 1800 604800 259200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0