91.36.ciberserver.com has no CNAME records.
Question and response
Question
dig 91.36.ciberserver.com. NS
Answer
The response has no answer records.
Authority
36.ciberserver.com. 10049 SOA ns1.ciberserver.com. status.ciberconceito.com. 2022071400 3600 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0