ns2.skystark.net has no MX records.
Question and response
Question
dig ns2.skystark.net. MX
Answer
The response has no answer records.
Authority
skystark.net. 10 SOA ns1.skystark.net. support.skystark.net. 1772003272 300 60 3600 10
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0