mail.tatech.co has no CNAME records.
Question and response
Question
dig mail.tatech.co. NS
Answer
The response has no answer records.
Authority
tatech.co. 3600 SOA sits.pro. tech.sits.pro. 2020071351 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0