ns1.cortel.cloud has no CNAME records.
Question and response
Question
dig ns1.cortel.cloud. NS
Answer
The response has no answer records.
Authority
cortel.cloud. 1257 SOA ns1.cortel.cloud. root.cortel.cloud. 2026020405 28800 7200 2419200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0