pd.sanet.sk has no MX records.
Question and response
Question
dig pd.sanet.sk. MX
Answer
The response has no answer records.
Authority
sanet.sk. 86400 SOA ns.cvt.stuba.sk. postmaster.stuba.sk. 2026012300 21600 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0