server.clauswitt.com has no MX records.
Question and response
Question
dig server.clauswitt.com. MX
Answer
The response has no answer records.
Authority
clauswitt.com. 600 SOA ns01.one.com. hostmaster.one.com. 2026030701 14400 3600 1209600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0