mx01.wcs.net.br has no CNAME records.
Question and response
Question
dig mx01.wcs.net.br. NS
Answer
The response has no answer records.
Authority
wcs.net.br. 3436 SOA ns4.wcs.net.br. abuse.wcs.net.br. 2026012201 43200 900 241920 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0