sip2.multimetro.pl has no MX records.
Question and response
Question
dig sip2.multimetro.pl. MX
Answer
The response has no answer records.
Authority
multimetro.pl. 3600 SOA dns.miconet.pl. das.miconet.pl. 2025070802 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0