pl.ua has no MX records.
Question and response
Question
dig pl.ua. MX
Answer
The response has no answer records.
Authority
pl.ua. 3600 SOA ho1.ns.pl.ua. dnsmaster.hostmaster.ua. 2008075181 3636 1212 1814400 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0