ns3.na.cloud.im has no MX records.
Question and response
Question
dig ns3.na.cloud.im. MX
Answer
The response has no answer records.
Authority
na.cloud.im. 300 SOA ns1.na.cloud.im. root.linmn.na.cloud.im. 264334 14400 7200 2419200 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0