ns.mtel.bg has no MX records.
Question and response
Question
dig ns.mtel.bg. MX
Answer
The response has no answer records.
Authority
mtel.bg. 300 SOA ns.mtel.bg. sysadmin.mtel.net. 2025120201 3600 900 1209600 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0