exim.wanex.net has no CNAME records.
Question and response
Question
dig exim.wanex.net. NS
Answer
The response has no answer records.
Authority
wanex.net. 6849 SOA main.wanex.net. hostmaster.wanex.net. 2024061000 10800 3600 1209600 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0