srv-de-3.nvme-servers.com has no MX records.
Question and response
Question
dig srv-de-3.nvme-servers.com. MX
Answer
The response has no answer records.
Authority
nvme-servers.com. 1800 SOA kaiser.ns.cloudflare.com. dns.cloudflare.com. 2396793114 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0