mta.nic.ir has no CNAME records.
Question and response
Question
dig mta.nic.ir. NS
Answer
The response has no answer records.
Authority
nic.ir. 3600 SOA ns1.nic.ir. admin.nic.ir. 2026030605 10800 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0