mail.42one.com has no MX records.
Question and response
Question
dig mail.42one.com. MX
Answer
The response has no answer records.
Authority
42one.com. 4800 SOA ns01.v-dns.de. hostmaster.v-dns.de. 2025121502 7200 3600 4800 4800
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0