ns.vistec.com has no MX records.
Question and response
Question
dig ns.vistec.com. MX
Answer
The response has no answer records.
Authority
vistec.com. 999 SOA ns.vistec.com. root.ns.vistec.com. 2023020301 86400 14400 1209600 999
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0