mx00.vrcore.net has no MX records.
Question and response
Question
dig mx00.vrcore.net. MX
Answer
The response has no answer records.
Authority
vrcore.net. 300 SOA dns103.ovh.net. tech.ovh.net. 2026022000 86400 3600 3600000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0