srv4.valuco.net has no MX records.
Question and response
Question
dig srv4.valuco.net. MX
Answer
The response has no answer records.
Authority
valuco.net. 300 SOA ns0.transip.net. hostmaster.transip.nl. 2023010900 86400 1800 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0