mail.sharktech.net has no CNAME records.
Question and response
Question
dig mail.sharktech.net. NS
Answer
The response has no answer records.
Authority
sharktech.net. 1743 SOA ns1.sharktech.net. admin.sharktech.net. 2022080902 300 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0