mails.vodafonenet.ro has no CNAME records.
Question and response
Question
dig mails.vodafonenet.ro. NS
Answer
The response has no answer records.
Authority
vodafonenet.ro. 672 SOA ns01.vodafonenet.ro. dnsadmin_ro.vodafone.com. 2010020307 10800 3600 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0