mx2.elpos.net has no CNAME records.
Question and response
Question
dig mx2.elpos.net. NS
Answer
The response has no answer records.
Authority
elpos.net. 1800 SOA dns.elpos.net. administrator.elpos.net. 2025032201 1800 3600 1209600 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0