mx3.grupofame.com has no CNAME records.
Question and response
Question
dig mx3.grupofame.com. NS
Answer
The response has no answer records.
Authority
grupofame.com. 10770 SOA dns33098.dizinc.com. root.server5.grupofame.com. 2026012201 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0