mail.host685-1.slaskdatacenter.com has no MX records.
Question and response
Question
dig mail.host685-1.slaskdatacenter.com. MX
Answer
The response has no answer records.
Authority
host685-1.slaskdatacenter.com. 1000 SOA ns1.slaskdatacenter.com. hostmaster.host685-1.slaskdatacenter.com. 2021052300 1000 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0