gra-01.rexum.space has no CNAME records.
Question and response
Question
dig gra-01.rexum.space. NS
Answer
The response has no answer records.
Authority
rexum.space. 1480 SOA elma.ns.cloudflare.com. dns.cloudflare.com. 2398372638 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0