preview.systec.ir has no MX records.
Question and response
Question
dig preview.systec.ir. MX
Answer
The response has no answer records.
Authority
systec.ir. 43200 SOA ns1.systec.ir. admin.systec.ir. 2021061982 36000 3600 1123200 43200
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0