proxy.rz.opal-consulting.com has no MX records.
Question and response
Question
dig proxy.rz.opal-consulting.com. MX
Answer
The response has no answer records.
Authority
opal-consulting.com. 3600 SOA a.xnameserver.de. hostmaster.inwx.de. 2026021501 10800 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0