ns2.cortel.cloud has no CNAME records.
Question and response
Question
dig ns2.cortel.cloud. NS
Answer
The response has no answer records.
Authority
cortel.cloud. 10714 SOA ns1.cortel.cloud. root.cortel.cloud. 2026020405 28800 7200 2419200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0