_spf.wy.sk has no MX records.
Question and response
Question
dig _spf.wy.sk. MX
Answer
The response has no answer records.
Authority
wy.sk. 3600 SOA ns1.wy.sk. root.wy.sk. 2026012101 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0