ns2.rasp.sh has no MX records.
Question and response
Question
dig ns2.rasp.sh. MX
Answer
The response has no answer records.
Authority
rasp.sh. 86400 SOA ns1.rasp.sh. a.rasp.sh. 2023042521 3600 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0