mail.cronosinternet.net has no CNAME records.
Question and response
Question
dig mail.cronosinternet.net. NS
Answer
The response has no answer records.
Authority
cronosinternet.net. 86 SOA ns1.cronosinternet.net. support.cronosinternet.net. 2024121201 3600 300 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0