auth4.nextlevelinternet.com has no MX records.
Question and response
Question
dig auth4.nextlevelinternet.com. MX
Answer
The response has no answer records.
Authority
nextlevelinternet.com. 1800 SOA auth1.nextlevelinternet.com. dns.nextlevelinternet.com. 2025070901 10800 3600 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0