ns2.ritternet.com has no MX records.
Question and response
Question
dig ns2.ritternet.com. MX
Answer
The response has no answer records.
Authority
ritternet.com. 600 SOA ns1.ritternet.com. hostmaster.ritternet.com. 2022102096 108 360 60 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0