mx1.cst.gov.sa has no MX records.
Question and response
Question
dig mx1.cst.gov.sa. MX
Answer
The response has no answer records.
Authority
cst.gov.sa. 600 SOA ns1.cst.gov.sa. admin.cst.gov.sa. 2026013105 3600 3600 1209600 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0