mail.tcv.bg has no MX records.
Question and response
Question
dig mail.tcv.bg. MX
Answer
The response has no answer records.
Authority
tcv.bg. 3600 SOA tcv.bg. root.tcv.bg. 2026012202 43200 900 1814400 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0