mail.boal.tech has no CNAME records.
Question and response
Question
dig mail.boal.tech. NS
Answer
The response has no answer records.
Authority
boal.tech. 1200 SOA ns1.boal.tech. ns2.boal.tech. 200 1200 1200 2419200 1200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0