ip.cybergrota.com.pl has no MX records.
Question and response
Question
dig ip.cybergrota.com.pl. MX
Answer
The response has no answer records.
Authority
ip.cybergrota.com.pl. 600 SOA ns1.itservice4u.pl. dns.rudna-net.pl. 2020093000 43200 900 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0