udns2.cscudns.org has no MX records.
Question and response
Question
dig udns2.cscudns.org. MX
Answer
The response has no answer records.
Authority
cscudns.org. 86400 SOA udns1.cscdns.net. hostmaster.cscdns.net. 2022110324 86400 86400 86400 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0