ip.campus-rv.net has no MX records.
Question and response
Question
dig ip.campus-rv.net. MX
Answer
The response has no answer records.
Authority
ip.campus-rv.net. 3600 SOA ns.campus-rv.net. admin.campus-rv.net. 2025092801 3600 900 3600000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0