mailsweeper.claro.com.ar has no CNAME records.
Question and response
Question
dig mailsweeper.claro.com.ar. NS
Answer
The response has no answer records.
Authority
claro.com.ar. 57 SOA ns1.claro.com.ar. nicmaster.claro.com.ar. 2023081713 300 300 1728000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0