is.hvfree.net has no MX records.
Question and response
Question
dig is.hvfree.net. MX
Answer
The response has no answer records.
Authority
hvfree.net. 1800 SOA ns1.hvfree.cz. info.hvfree.net. 2026022300 3600 3600 4000 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0