f.nic.tech has no MX records.
Question and response
Question
dig f.nic.tech. MX
Answer
The response has no answer records.
Authority
nic.tech. 3600 SOA ns0.centralnic-dns.com. hostmaster.centralnic-dns.com. 1771511616 300 300 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0