dns4.grz.at has no MX records.
Question and response
Question
dig dns4.grz.at. MX
Answer
The response has no answer records.
Authority
grz.at. 1800 SOA dns1.grz.at. hostmaster.grz.at. 2017081246 1800 600 1209600 1800
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0