ns.nextra.sk has no MX records.
Question and response
Question
dig ns.nextra.sk. MX
Answer
The response has no answer records.
Authority
nextra.sk. 900 SOA auth1.ns.benestra.sk. hostmaster.benestra.sk. 2024020103 86400 180 1209600 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0