mail.w-net.us has no CNAME records.
Question and response
Question
dig mail.w-net.us. NS
Answer
The response has no answer records.
Authority
w-net.us. 382 SOA ns-us.wnet.pro. hostmaster.w-net.us. 2026010800 1800 1800 3600000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0