dns4userver.com has no MX records.
Question and response
Question
dig dns4userver.com. MX
Answer
The response has no answer records.
Authority
dns4userver.com. 3600 SOA ns1.dns4userver.com. server.serverplan.com. 2025030406 10800 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0