mail.rdslink.ro has no CNAME records.
Question and response
Question
dig mail.rdslink.ro. NS
Answer
The response has no answer records.
Authority
rdslink.ro. 9884 SOA ns.rdsnet.ro. dns-adm.rdsnet.ro. 2026030501 10800 3600 2016000 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0