mx.mirohost.net has no TXT records.
Question and response
Question
dig mx.mirohost.net. TXT
Answer
The response has no answer records.
Authority
mirohost.net. 900 SOA nsa2.srv53.net. support.dnshosting.org. 1771865247 1800 600 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0