mail-backup.spk.cz has no MX records.
Question and response
Question
dig mail-backup.spk.cz. MX
Answer
The response has no answer records.
Authority
spk.cz. 3600 SOA ns4.selectsystem.cz. hostmaster.selectsystem.cz. 2025062305 14400 7200 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0