ns1-191-232.superdnsserver.net has no MX records.
Question and response
Question
dig ns1-191-232.superdnsserver.net. MX
Answer
The response has no answer records.
Authority
superdnsserver.net. 900 SOA ns1.superdnsserver.net. hostmaster.superhosting.bg. 2013076263 3600 600 2419200 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0