mx.uzmanposta.com has no CNAME records.
Question and response
Question
dig mx.uzmanposta.com. NS
Answer
The response has no answer records.
Authority
uzmanposta.com. 3167 SOA ns1.dnssunucu.com. hostmaster.pusula.net.tr. 2023121801 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0